In Search of Perfect Growth Media for Baker's Yeast Production: Mapping Patents



Abstract:  Baker's yeast is a key ingredient for bread and, on the long term, changes in its manufacturing process had a major impact on the baking industry. As shown by a review of 236 patents filed between 1900 and 2009, the development of suitable growth media for baker's yeast was critical to improve its acceptability by the baking industry mainly through reduced cost and improved appearance (pale color). Based on the abandon of patenting activity on artisan yeast production in dough, acceptable commercial baker's yeast appeared on the North American market around 1920, but probably 5 to 15 y earlier in Europe partly because German inventors were the most active to develop growth media for baker's yeast. During the same period, grain-based media were replaced by diluted molasses that was cheaper. In the following 20 y, inventors put much energy on molasses clarification and miscellaneous sources of nitrogen to supplement it. Although molasses remains the basic raw material for baker's yeast manufacturing, alternatives are still sought for this application. In the early patent literature, cases were found where several inventors claimed intellectual property rights for the same invention described in patents filed in different countries and languages, which suggests that only thorough reading of patent specifications may distinguish inventorship from licenses and thus truly estimate patenting activity.


In industrialized countries, yeast-raised bakery products are highly standardized commodities. However, before home baking was replaced by commercial bread making in the early days of the 20th century, bread appearance and taste were variable partly because quality of baker's yeast was not thoroughly controlled (Gélinas 2010a). During that period, yeast was rather expensive so there was a need to reduce its costs by searching ways to increase its yield at the production plant, including cheap raw materials for preparing growth media.

Yeast quality improved much when suitable fermentation processes were developed (Frey and others 1936). It was found that diluted molasses supplemented with nitrogen and other minor nutrients was the most appropriate growth medium for yeast. Yeast has been a key microorganism in microbiological sciences and it is important to consider historical aspects to better understand its role (Barnett 2003). However, little information has been published on the overall evolution of yeast technology, including factors contributing to its cost reduction and quality improvement that had a major impact on modern bread production. Review of the patent literature is an original way to better understand technology trends because, contrary to scientific papers, patents would be the main source of new technical knowledge (Sternitzke 2009).

The objective of this study was to extensively review the evolution of patenting activity on growth media for baker's yeast and, indirectly, to see how it impacted the baking industry. Covering the years 1900 to 2009, which correspond to modern yeast technology, this study is a follow-up to the review of early patent literature on yeast manufacture from the 19th century (Gélinas 2010a). This paper is part of a series of reviews on baker's yeast, including strains and specialty ingredients (Gélinas 2009), and management at the bakery plant (Gélinas 2010b).


Background information and search criteria

A patent is a legal document describing technical information. This review is based on “patent families” that combine specifications describing the same basic invention. Contrary to other reviews on this topic (Gélinas 2009; 2010a; 2010b), these related patents are presented according to the earliest filing date, not the publication date. This helped to determine priority of related inventions, trace back the original inventors, and better judge technology trends and inventors’ incentives according to time. During the preparation of this review, it was found that in countries such as Germany and Austria, there were large delays between filing dates and publication dates, sometimes more than 5 y, especially during the World War I and II periods around 1914 to 1918 and 1939 to 1945.

In several patent offices, priority of inventions disclosed in specifications filed after 1900 was generally checked before the acceptance and publication of patents. However, in Great Britain (GB), specifications of nonaccepted patents were published until 1883 but the complete specification of one nonaccepted GB patent issued in 1924 was found (GB 192085). GB patents with an application date earlier than 1916 were identified both by the year of application (rather than year of publication) and by serial number; afterwards, a new and continuously numbered sequence was introduced (Rimmer and Van Dulken 1992).

This review did not attempt to give a full account of yeast technology because patents represent only a fraction of total inventions. This has been covered elsewhere (Reed and Nagodawithana 1991; Gélinas 2006). Patents were rather seen as privileged and timely evidence of the evolution of interests and concerns in the yeast manufacturing industry, especially in the years 1900 to 2009. This work also completes the review of patents published before 1900 (Gélinas 2010a). Most of the patents were obtained through search in data bases, such as esp@cenet and Depatis. Some French patents were ordered through INPI (Institut Natl. de la Propriété Intellectuelle, Paris). More details on the methodology are given in Gélinas (2010a). Near the completion of this review, it was possible to get access to a book published by Wagner (1936) that includes a brief abstract of many patents issued prior to 1936 on baker's yeast.

Evolution of Patenting Activity According to Year

Number of patents

Overall, 356 patents on growth media for baker's yeast were found, including 236 filed between 1900 and 2009 or twice the number of patented inventions in the 19th century (Table 1). These trends were less clear when calculations were based on the publication date rather than the filing date (not shown). The most active period of patenting activity lasted about 65 y, from 1875 to 1939, with an average of 20 patents per 5 y or 4 patents per year. Since that period, interest of inventors for yeast growth media has considerably diminished with only 1 patent per year.

Table 1–.  Categories of patents on growth media for baker's yeast according to filing date.a
YearSourdough starterBrewer's yeast treatmentBasic liquid mediaMolasses treatmentNitrogenAdjunctsTotal
  1. aPatents prepared by the same inventor and representing variations or improvements of the same invention were combined into a single patent for invention.

  2. bInformation on patents filed before 1900 was adapted from Gélinas (2010a). Since the publication of that review, 7 more patents were found and counted in the table above: 1 patent on sourdough (1883. DE 22625; filed in 1882 by Jäkel and von Michaelis, from Germany), 5 patents on basic liquid media (1883; DE 25211; filed in 1883 by Partenheimer, from Germany); (1888; DE 43689; filed in 1887 by Bauer, Kruis, and Jahn, from Hungary); (1891; DE 58159; filed in 1890 by Hradil, from Germany); (1892; DE 63351; filed in 1891 by Braun, from Germany); (1893; DE 68702; filed in 1892 by Geduld, from France), and 1 patent on the addition of nitrogen (ammonium sulfate) to growth media (1895; AT Privilege 45/4047; filed in 1895 by Fritsche, from Austria).

Before 18504 1   5
1850 to 18542     2
1855 to 1859613   10 
1860 to 186422    4
1865 to 18692 4   6
1870 to 1874223   7
1875 to 1879753 3119 
1880 to 1884 2b1 10b 2 15 
1885 to 1889 2  8b 1 11 
1890 to 189422 13b12 20 
1895 to 18997145 3b121 
1900 to 19042310 16123 
1905 to 190911712 12 
1910 to 1914 7823121 
1915 to 191941724119 
1920 to 1924  11 12 6231 
1925 to 1929 3810 4126 
1930 to 193412410 6225 
1935 to 193911351617 
1940 to 1944 333 110 
1945 to 19491 211 5
1950 to 1954  2  35
1955 to 1959   1 12
1960 to 1964  1   1
1965 to 1969    112
1970 to 1974  11  2
1975 to 1979  6 1 7
1980 to 19841  2  3
1985 to 1989  41 16
1990 to 1994 131  5
1995 to 1999 14  27
2000 to 2004  2  24
2005 to 2009  1 113
Subtotal (Before 1900)36 16 49 611 2120  
Subtotal (1900 to 2009)11 23 87 53 36 26 236  
Total47 39 136  59 47 28 356  

A very important concern in the 19th century, artisan recipes such as sourdough-type leavens appeared to have ended around 1920, confirming that the quality of commercial baker's yeast was acceptable during this period. However, interest for reusing brewer's yeast in baking appeared to last until 1945, which indicates that cheap sources of yeast for baking applications were still looked for during the Second World War.

After 1900, the most popular topics were basic liquid media (others than molasses) and, to a lesser extent, molasses treatment, organic nitrogen sources, brewer's yeast treatment, and adjunct materials. Between 1920 and 1934, there was a major interest in molasses purification techniques for yeast manufacturing, which suggests that this raw material had been massively adopted by the yeast industry but techniques for its cleaning needed improvement. During the same period, inventors continued to show interest in media supplementation with organic nitrogen sources (malt and others), but this practice stopped when acidity problems associated with the use of cheaper inorganic nitrogen sources were solved. Since the 1940s, inventors have mainly been interested in molasses substitutes, molasses treatments, and growth factors (adjuncts).


Country of origin

European inventors were at the forefront of the development of yeast growth media (Table 2). With 20% to 25% of all patents on this subject (80 patents), German natives were the most active inventors, followed by citizens from the United States (59 patents), GB (48), France (41), and Austria (32). After 1900, Austrians became the 3rd most active inventors in this area, while those from GB and France lost much interest on baker's yeast technology.

Table 2–.  Country of origin of inventors on growth media for baker's yeast according to filing date of patents.
  1. Based on Recommended Standards of the World Intellectual Property Organization, the following two-letter codes for the representation of States have been used for patent numbers and country of origin of inventors: AT = Austria; AU = Australia; BE = Belgium; CA = Canada; CH = Switzerland; CS = Czechoslovakia; Danzig = free city of Danzig, now in Poland; DD = German Democratic Republic; DE = Germany; DK = Denmark; EG = Egypt; FI = Finland; FR = France; GB = Great Britain; HU = Hungary; IE = Ireland; IT = Italy; JP = Japan; LI = Liechtenstein; NL = Netherlands; NO = Norway; PL = Poland; RO = Romania; RU = Russia; SE = Sweden; US = United States of America; YU = Yugoslavia; ?= unknown. For patents with inventors from different countries, only the country of the 1st inventor was considered.

  2. a These data were partly adapted from Gélinas (2010a).

Before 1900a251733206 23133 32 FI; ?120
1900 to 190492226  2        23
1905 to 190942222           12
1910 to 19147 246  1      1 21
1915 to 191925123 11 1 1 1 FI19
1920 to 1924510152    1 4   IT; RO; Danzig31
1925 to 192944312   11    2IE; PL; NO; FI; RO; IT; YU (2)26
1930 to 1934112123     2 1  ?; LI; PL25
1935 to 1939491     2      ?17
1940 to 19441311    3      AU10
1945 to 1949   11  11      EG5
1950 to 19541111     1      5
1955 to 19591   1           2
1960 to 1964 1              1
1965 to 1969     1        1 2
1970 to 19741    1          2
1975 to 1979 1   6          7
1980 to 1984 1   2          3
1985 to 198941             DD6
1990 to 1994      3        YU; AU5
1995 to 19991    23      1  7
2000 to 2004     22         4
2005 to 2009     11        AU3

German inventors were involved in all aspects of growth media for yeast manufacturing. They showed little interest for kitchen or artisan sourdough-type starters that had little industrial potential, which confirms trends from the 19th century (Gélinas 2010a). These inventors were generally living in the East (mainly Berlin but also Dresden) or, to a lesser extent, in the West (close to the Belgium border) and the North (mainly Hamburg). Considering the importance of the brewing industries in the North, these citizens were particularly interested in treating brewer's yeast on a large scale for baking applications.

Most of the U.S. inventors came from the Eastern states, in particular New York (1 out of 3). Particularly between 1920 and 1940, they were mainly interested in nitrogen and adjuncts (growth factors) with 30% to 35% of patents filed on this subject.

Before the year 1900, GB was the leader in patented inventions on growth media for baker's yeast, even if several of these specifications described artisan recipes (Gélinas 2010a). After 1905, there was a major drop of patenting activity from this country, except for brewer's yeast treatment for baking applications. Most British inventors came from London or the South of the country.

From France, about two-thirds of the patents were on alternative liquid media, not based on molasses. These inventors were generally based in Paris (Seine) or the North region. After the year 1900, in Vienna (Austria), there was a major interest in patents on growth media for yeast, particularly molasses treatment and molasses-alternative media. After 1975, significant patenting activity was seen in Japan (15 patents) and Russia (12 patents) on the development of alternative liquid media (molasses substitutes). Inventors from Northern European countries, such as Sweden, also showed interest in techniques for the purification of molasses for baker's yeast manufacturing.

Germans and, to a lesser extent, Austrians often filed patent applications in several foreign countries contrary to inventors from the United States, GB, or France who rarely filed patents outside of their countries (Table 3). Despite the importance in the field, few foreign inventors filed patents in Germany or Austria. In addition to patenting in their own country, most of the foreign citizens interested in growth media for baker's yeast filed patents in GB and France. Foreign patent applications by U.S. citizens were generally filed in GB.

Table 3–.  Foreign countries where patents on baker's yeast growth media were filed according to the origin of inventors.a
Origin of inventorsMajor country where patents were filedTotal
  1. aOnly data for inventors from the most active countries are shown, without reference to patent applications filed in their own country.

US 122  1 116
GB1522  1 11
FR 242   19
AT9377   127


About one-third (75) of the patents on yeast growth media were assigned to companies or research institutes, but only 9 of them owned 3 or more patents (Table 4). Most of the patents on molasses treatment and adjuncts were developed by companies and this suggests that these were critical issues for yeast manufacturers and particularly between 1920 and 1945.

Table 4–.  List of the major industrial assignees on growth media for baker's yeast for patents filed between 1900 and 2009.
Assignee (city, country)Application (filing y)
Aktiebolaget Separator (Stockholm, Sweden); later (1963) Alfa Laval ABMolasses (1935; 1937; 1942)
Aktieselskabet Dansk Gaerings-Industri (Copenhagen, Denmark)Molasses (1927; 1927); adjuncts (1951)
Nippon Beet Sugar Mfg. (Tokyo, Japan)Liquid media (1976; 1977; 1996)
Oriental Yeast Co., Ltd. (Tokyo, Japan); Oriental Yeast Co. Ltd, and Soken Co. Ltd; Oriental Yeast Co. Ltd and Matsutani Kagaku KogyoLiquid media (1977; 1998); molasses (1974)
Ramesohl & Schmidt Aktiengesellschaft (Oelde, Westphalia, Germany); Westfalia Separator AGMolasses (1931; 1931; 1932; 1937)
Standard Brands Inc. (Dover, Del., U.S.A.); see also The Fleischmann Co.Liquid media (1938); molasses (1940); adjuncts (1939; 1939; 1939)
The Fleischmann Co. (New York, U.S.A.); see also Standard Brands Inc.Liquid media (1919; 1922); molasses (1923; 1925); nitrogen (1919)
Verein der Spiritus-Fabrikanten in Deutschland (Berlin, Germany)Liquid media (1913); nitrogen (1903; 1910); adjuncts (1915)
Vereinigte Mautner Markhof'sche Presshefe Fabriken (Vienna, Austria)Liquid media (1947); molasses (1922; 1924); adjuncts (1933)

With 10 patents, the most active industrial group was The Fleischmann Co. from the United States, a company that would become Standard Brands Inc. in 1929. As will be shown below, in addition to these 10 patents, the Fleischmann/Standard Brands group owned the legal rights for 5 more inventions patented in Europe between 1915 and 1928, obtaining what may be called exclusive licenses for these inventions in the United States. Most of these licenses were on molasses treatment that confirms that this matter was very important for this yeast manufacturer. In the early days of baker's yeast technology, this was an unusual example of technology transfer and indicates that the Fleischmann/Standard Brands group was well aware of patents issued in Europe, especially in Germany. Before the year 1900, this company had 3 patents on yeast separation from growth media (Gélinas 2010a). Later, it would also be very active in developing other patented inventions for the yeast industry.

Many of the yeast manufacturers developed cartels in their respective countries. In the United States, the Fleischmann Co. or Standard Brands was a leader in yeast manufacture, as was Distillers Co. in the United Kingdom (Weir 1991). Standard Brands had commercial links with The Intl. Yeast Co. Limited (London) and The Distillers Co. Limited (Edinburgh) from the United Kingdom (Weir 1991), as confirmed by multiple identical patents published simultaneously in the United States and United Kingdom.


During the preparation of this review, it was found that identical versions of the same patented invention were authored by different individuals or companies, in different countries. This suggests that exclusive rights on the basic invention were sold or licensed to other parties. These 21 publications (licenses) were compiled because there were possibilities to overestimate the number of patented inventions.

Table 5 lists the most difficult cases to spot because there were no cross-references between identical patent specifications granted to different “inventors” or “applicants” that did not appear to be linked. In total, 10 cases on patents filed between 1898 and 1941 involved identical patents signed by different applicants in various countries and languages, without acceptable reference to the priority file. Only a thorough reading of patent specifications permitted to distinguish between true inventors, legal owners of the rights (assignees), and those who appeared to have bought these rights, in other countries, in second hand from assignees (licensees). Most of these patents did not mention the existence of a priority file by disclosing the priority date and country. This suggests that these patents (licenses) should not have been granted because they did not make proper reference to priority files (patents) in foreign countries. In the recent patent literature, these problems appeared to have been solved because complete information on the priority file is now disclosed. Patent protection of the same invention by 2 different applicants has been considered to be rare in the recent years (Germinario 2011).

Table 5–.  Cases of licenses (1900 to 2009) in which several patent applicants claimed the same invention on baker's yeast growth media, without proper citation of the priority file.a
Priority dateInventor or first to file; patent nr.Licensee; patent nr.; filing dateSubjectRemark
  1. aExcept where indicated, no information was available on the priority file. In the absence of clear cross-references between applicants, their respective status (inventor; licensee) were based on filing dates, specifications, and claims. When identical versions of the same “basic patent” were issued in several countries, patent numbers are given in parentheses and without reference to the publication year. Identification of most of the country codes is given at the bottom of Table 2.

August 6, 1898Fuhrmann; DE 108334 (AT 1212)Kafka; GB 189915451; filed July 27, 1899Molasses treatmentApplicants from Austria worked together with Marbach on a similar topic and were co-inventors for AT 516 (DE 113977) filed December 19, 1898
December 13, 1911Jacoby (1913); Diamalt-Aktien-Gesellschaft; US 1078288 (AT 65415; CH 62339; FR 450988)Malz-und Nährpräparategesellschaft mit Beschräenkter Haftung; GB 191226005; filed November 12, 1912; cites priority date in GermanyBrewer's yeast treatmentThese were probably joint companies established in Sonnenstrasse, Munich, Germany
February 13, 1912Becco Gesellschaft für Hefeveredelung m.b.H.; DE 277639; CH 65912 (FI 5710)#1. Ruf; CH 59662; FR 440841; filed February 22, 1912 (CH) and March 2, 1912 (FR)
#2. Liebert; GB 191207272; filed March 25, 1912
Brewer's yeast treatmentThis appears to be an invention by Ruf (Switzerland) but its rights were probably owned by the Becco group (Germany) that was the first to file and to license it to Liebert (Austria)
November 23, 1922Langemeyer; GB 207546 (FR 573544)Knappe; CA 243096; filed October 14, 1923AdjunctsLink between applicants is unknown but they both lived in Mettingen, Germany
June 14, 1926Eijkenskjöld; Aktiebolaget Bästa; SE 66792 (US 1703272; DE 617670)Vereinigte Mautner Markhof'sche Presshefe Fabriken und Aktiengesellschaft Ignaz Kuffner & Jacob Kuffner für Brauerei, Spiritus-und Presshefefabrikation; AT 125163; filed June 4, 1927; cites priority date in SwedenLiquid mediaLink between applicants from Sweden (inventor) and Austria (licensee) is unknown
October 30, 1930 and March 20, 1931Bergl; CH 157929 (FR 723515; AT 143878)Bermann, assigned to Butacon Aktiengesellschaft; US 2053596; filed October 30, 1931; cites priority date in Switzerland rather than the true priority date in Germany (patent not found)Brewer's yeast treatmentLink between applicants from Germany (inventor) and Czechoslovakia (licensee) is unknown
June 27, 1933 (HU) and November 13, 1934 (GB)Dinich; HU 111224; GB 434249 (FR 781220; CH 182950; DK 51823)#1. Vogelbusch; AT 149531; filed June 7, 1934; cites priority date in Hungary
#2. Fuchs; US 2072748; filed November 14, 1934
Brewer's yeast treatmentLink between applicants from Hungary (inventor), Austria (licensee), and Czechoslovakia (licensee) is unknown; in the Vogelbusch's version, specification is different
January 22, 1941Deloffre; Fermzymtera Société Anonyme Holding; AU 114926 (FR 885959; GB 553908; US 2367931; DE 971590; DK 82072; CA 420018)Effront; AT 218451; filed December 29, 1953; cites priority date in AustraliaLiquid mediaLink between applicants from Australia (inventor) and Switzerland (licensee) is uncertain

Table 6 lists 11 more cases where legal rights over an invention have clearly been transferred or licensed to others, generally companies. Contrary to Table 5, information on the priority file was available and it was possible to distinguish inventors from licensees. In general, the disclosed inventions were first assigned to a manufacturer who granted the exclusive rights to another company established in a foreign country.

Table 6–.  Cases of licenses (1900 to 2009) in which several patent applicants claimed the same invention on baker's yeast growth media, with proper citation of the priority file.a
Priority dateInventor or first to file; patent nr.Licensee; patent nr.Subject
  1. aWhen identical versions of the same ‘’basic patent’’ were issued in several countries, patent numbers are given in parentheses and without reference to the publication year. Identification of most of the country codes is given at the bottom of Table 2.

May 22, 1902Kruis and Firma F. Ringhoffer; AT 15051Goldschmidt; AT 43081 and AT 51923 are additions to AT 15051; filed January 27, 1909 and February 25, 1910Liquid growth media
May 28, 1902Kues; AT 14061 (DE 158655)Wenck; DE 186163 is an addition to DE 158655; filed September 4, 1906Nitrogen
August 20, 1915Hayduck; Verein der Spiritus-Fabrikanten in Deutschland; DE 303252The Fleischmann Co.; US 1449104 (CA 238177); filed October 30, 1920Adjuncts
April 7, 1920Wohl; DE 402250 (and other patents)#1. van Lier; NL 12996; filed February 24, 1921Molasses
  #2. The Fleischmann Co.; US 1449134; filed August 31, 1921 
January 19, 1922Ransohoff; The Fleischmann Co.; US 1722858 (CA 229401)The Intl. Yeast Co. Limited; GB 192085 (not accepted); filed January 18, 1923Liquid media
August 29, 1922Klein; FR 565464 (and other patents)#1. van Lier; NL 13773; filed April 25, 1923
#2. The Fleischmann Co.; US 1722803 (CA 250753); filed August 17, 1923
Liquid media
December 23, 1922Hamburger and Kaesz; GB 209034Standard Brands Inc.; US 1770402; filed October 12, 1923Molasses
June 25, 1928Bennett and Peake; The Distillers Co.; GB 319641 (FR 677228)Standard Brands Inc.; US 1860832; filed June 12, 1929Molasses
August 20, 1938Bergedorfer Eisenwerk A.G. Astra-Werke; unknown DE patent numberAktiebolaget Separator; GB 531931; filed August 8, 1939Molasses

With only few exceptions, cases of licenses presented in Table 5 and 6 describe inventions on the development of molasses treatments, basic liquid media, and brewer's yeast treatment. This suggests that these topics were very important to the yeast industry. As mentioned above, The Fleischmann Co./Standard Brands Inc. group owned 5 licenses from European individuals, research institutes, or companies. In addition to licenses described in Table 5 and 6, earlier reports on baker's yeast media in the 19th century (Gélinas 2010a) showed that one more license was obtained by Charles Fleischmann from Eusebius Bruun. For yeast growth media, this indicates that licenses disclosed in the patent literature were mainly popular between 1896 and 1953.

In general, licenses were filed less than 12 mo after the priority date that indicates that cases of licenses described in Table 5 and 6 met acceptable delays for patent filing in various countries. From Table 6 and according to Ladas (1975), exceptional cases included acceptable additions to patents in Austria and Germany, and extended filing delays due to World War I (in the United States, filed in 1921 by The Fleischmann Co. and probably granted under the provision of the Nolan Act of March 3, 1921) and World War II (in Austria, filed in 1953 by Effront).


A special case was seen with a patent originally filed in 1941 in Australia by Marcel Deloffre (Table 5). This technology found many applications in the yeast industry (White 1954). In 1953, an addition to the original patent was filed in Austria by Ivan Effront, not Deloffre. This legal document was accepted only in 1959 and published in 1961. Except for the priority date that was indicated, Effront's patent did not specifically refer to the original Australian Deloffre's patent number or any of the other versions issued in at least 6 other countries. Based on careful reading and comparison, these Australian (Deloffre) and Austrian (Effront) patents described the same basic invention even if claims were not identical. To complicate matters, in 1960 Deloffre filed another patent in Luxembourg and other countries, including Austria, in 1961. This second patent by Deloffre was rather a follow-up to the original patent filed in 1941. It was probably filed because the legal rights over the basic invention were about to expire after 15 to 20 y.

The exact nature of the business relationship between Marcel Deloffre and Ivan Effront is unknown but Deloffre, a chemical engineer from France, arrived in Australia in 1929 to establish the “Effront yeast process” named after Jean Effront (1855 to 1931), the father of Ivan Effront and a renowned Belgian scientist born in Russia. The so-called Effront process had no connection with the invention claimed by Deloffre. However, around June 1940, Deloffre was manager for Effront Yeast Pty (South Yarra, Victoria, Australia). Probably as part of his job, he developed its process before moving to Luxembourg where he died in the early 1960s. A chemist, Ivan Effront (1898 to 1985) was born in Belgium and lived in France and Switzerland.

This example illustrates that, besides the description of specific technologies, patenting activity reflects personal relationships between citizens with close business interests. However, it may be difficult to trace inventorship when reviewing multiple versions of the same patent in different languages. In this case, family patent for Deloffre's invention included not less than 17 versions of identical or closely related specifications.

A question of legal rights

Unlike scientific publications, authorship of patents is not fixed and the same text may be published several times in legal texts filed in different countries. In the world of intellectual property, an “inventor” is someone who has contributed to the conception of the basic ideas behind an invention, which might be legally protected by a patent allowing a monopoly on the commercialization of this idea in a specific country and for a limited period of time, generally 20 y (Le Moal 1999). Patents are legal publications describing exclusive rights on an invention in a specific country. However, inventors may not own the rights of the so-called invention because these rights have been assigned to a specific employer or sold (licensed) to other parties.

Prior to 1950, especially when a company owned the legal rights of an invention and filed a patent, the names of the individuals (inventors) were generally not mentioned, except, for example, in patents filed in the United States. Indirectly, this illustrates that patent examiners had a difficult task in determining novelty aspects when patent applications signed by different authors were written in different languages and filed in several countries. In this context, it may be easy to overestimate patenting activity (number of patents) in a sector unless specifications and claims are thoroughly compared. Especially with the older patent literature, filing date (priority) of a patent is very helpful to determine inventorship.

Sourdough Starters (Artisan)

Table 7 presents patents issued after 1900 on artisan yeast production in dough. Those inventions were close to recipe development and did not differ much from those proposed in the 19th century (Gélinas 2010a). Seeded or not with yeast, the most popular ingredients were potatoes and, to a lesser extent, flours and fruits from miscellaneous sources.

Table 7–.  Patents published between 1900 and 2009 on artisan “yeast” production in cereal- or plant-based fresh dough.a
Inventor (publication y); priority dateCountry (city)Patent nr.Raw materials
  1. aLinked to the inventor and publication year (left column), patent number refers to the earliest publication of the invention. Patents are listed according to filing date of the invention (priority). In case of multiple publications and when available, the country of earliest filing is mentioned. For some entries, details of the main invention were published in several “basic patents” forming a “patent family.” When identical versions of the same basic patent were issued in several countries, patent numbers are given in parentheses and without reference to the publication year. Identification of most of the country codes is given at the bottom of Table 2.

Proskauer (1900); June 15, 1899DE (Berlin)GB 189912518 (AT 898)Milk and kefir bulbs (yeast seed)
Bordua (1900); July 14, 1899CA (Saint-Hyacinthe, QC)CA 68537Sugar, potatoes, and salt; with seed yeast
Priest (1900); December 29, 1899US (Imogene, Iowa)US 646761Buttermilk, cornmeal, and potato starch; with seed yeast
Heilenman (1901); February 27, 1901US (Louisville, Ky.)US 690279Corn meal, potato flour, bicarbonate of soda, sodium chloride, sugar, and anise flour; no seed yeast; salt-rising yeast (“yeast-flour”)
Arzt and Wilding (1902); June 13, 1901GB (London)GB 190112099Steamed, mashed, saccharified, and aerated potatoes or cereals (crushed kernels or flour); no seed yeast
Foit (1907); April 8, 1907US (Ironton, Ohio)US 863976Cooked potatoes seeded with leaven (hops, flour, and malt); no yeast seed
Heller (1916); February 11, 1915RU; US (Los Angeles, Calif.)US 1177323Boiled extract (figs, raisins, and hops), corn flour, and wheat bran; with seed yeast
Lumsden (1917); December 4, 1916US (Seattle, Wash.)US 1226347Fermented extract (“grain wine”) prepared from flour (rice, corn, wheat), malt, and sugar; no seed yeast
Risse (1918); July 3, 1918US (Rothsay, Minn.)CA 187628Boiled grated potatoes, hops extract, sugar, and salt; with seed yeast
Gagnon and Gosselin (1920); priority date unknownCACA 195910Hops extract, flour, sugar, galette royale, and mashed potatoes; no seed yeast
Coulter (1934); priority date unknown? (unknown)CA 346439Extract of potatoes (boiled and mashed), flour, sugar, mashed potatoes, and yeast or hop yeast (extract from boiled hops)
James (1936); priority date unknown? (unknown)CA 358092Extract of saccharified potatoes, starch, and molasses; with seed yeast
Minacoulis (1950); November 17, 1947EGFR 955756Starchy materials, such as potatoes or cassava, seeded with brewer's yeast and treated with UV light
Kizawa and Ishigami (1986); assigned to Nisshin Flour Milling; June 30, 1982 (JP)JP (Tokyo)CA 1209850Alcohol-free beer with koji and miscellaneous ingredients (apples, onions, sugar, salt, boiled potatoes, and cereal flours); no seed yeast

Historical context

Easy to prepare and generally compressed into tablets or dried, these “yeast substitutes” were developed because commercial yeast was judged too expensive. Inventors also considered that yeast quality was too variable, including gassing power, keeping properties, color, and taste. These alternative preparations were also intended to inhabitants from rural sectors that could not get commercial pressed yeast prepared in large yeast manufacturing operations. Based on Table 1 and 7, it is striking that as much as 13% (47) of the 356 patented inventions on yeast growth media described very simple recipes. Developed by individuals, these patents were easy to bypass, hard to protect, and offered little potential for licenses and to recover costs of the patenting procedure.

As mentioned earlier, inventions on sourdough-type yeast appeared to cease around 1920 (Table 1). This suggests that, around that period, the quality of industrial baker's yeast had improved enough to discourage inventors to propose new ideas on kitchen-type yeast formulations. In Europe, interest for such kitchen-type sourdough starters appeared to end much earlier (1901) than in North America (1918 to 1920). This might reflect differences in quality, cost, and availability of commercial yeast in these regions. A phenomenon specific to the United States, the first vending machines for pressed yeast were introduced around 1915, which may also indicate that commercial baker's yeast of sufficiently acceptable quality was available around that time in this country (Gélinas 2010b).

Brewer's Yeast Treatment

Table 8 presents patents on treatments for brewer's yeast as an alternative to growing baker's yeast from scratch. Mainly artisanal, interest for debittering techniques for brewer's yeast was small, but constant for about 100 y, until about 1944 (Table 1). Between 1900 and 1915, patents on the use of brewer's yeast for bread applications were mainly developed by British and German inventors; this confirms the lasting interest of British citizens in this subject since the 19th century (Gélinas 2010a). On an industrial scale, between 1930 and 1945, there appeared to be a renewed interest for such treatments, especially in Germany.

Table 8–.  Patents published between 1900 and 2009 on the treatment of brewer's yeast for bakery applications.
Inventor (publication y); priority dateCountry (city)Patent nr.TreatmentaDetailsb
  1. aC = chemical treatment; F = fermentation; M = mechanical treatment; O = others.

  2. bLarge-scale treatment of brewer's yeast, except where indicated (artisanal; distiller's yeast).

Norgaard (1900); March 30, 1899GB (Odiham)GB 189906939C; MCarbonate of soda or ammonia, with aeration
Raben and Wrede (1902); March 4, 1900DE (Hamburg)DE 130299CMagnesium hydroxide; artisanal
Brunt (1902); November 2, 1901GB (Burton-on-Trent)GB 190122116CBorax or alkali
Wrede and Offersen (1903); September 18, 1902DE (Flensburg)GB 190220365C; M; FAeration under alkaline conditions and fermentation in an acidified sugar syrup
Sarnighausen (1908); August 19, 1906DE (Hamburg)DE 194443C; MTartaric acid, with aeration
Stevenson (1911, 1913, 1917, 1918); November 29, 1910GB (Acton)GB 191027782; GB 191200989; GB 106531; GB 113486CFormaldehyde and calcium carbonate; activation in a grain-based wort
Erdmann and Schmuck (1912); Erdmann (1912); May 11, 1911 (GB)DE (Berlin)GB 191111424 (US 1045689)C; M; OAeration in a weak acid solution, under electric current
Jacoby (1913); assigned to Diamalt-Aktien-Gesellschaft (1914); licensed to Malz-und Nährpräparategesellschaft mit Beschräenkter Haftung (1913); December 13, 1911 (DE)DE (Munich)US 1078288 (AT 65415; CH 62339; FR 450988; GB 191226005)CPercarbonate of sodium (persalt)
Ruf (1912a, 1912b; CH and FR); assigned to Becco Gesellschaft für Hefeveredelung m.b.H. (1914; DE, CH, and FI); licensed to Liebert (1913; GB); February 13, 1912 (DE)CH (Basel); DE (Gebweiler); AT (Vienna)CH 59662; FR 440841 (DE 277639; GB 191207272); CH 65912 (FI 5710)C; FActivation in a nutritive solution (sugar, rye flour, and potatoes); may be treated with amyl acetate or pineapple ether; brewer's yeast or others
Barbet (1914); November 5, 1912FR (Paris)FR 461742M; FWashing with salt or sugar, and activated in an aerated wort (cereals)
Nydrle and Roth (1913); November 23, 1912 (AT)AT-HU (AT; Prague)CA 147402 (AT 67436)C; MAcidification, aeration in nutritive media, and sorting
Docherty (1914); May 1, 1914GB (Burton-on-Trent)GB 191410774CWashing with a weak alkaline solution (carbonate of ammonia) and mixing with wood charcoal; for dietetic and other purposes; artisanal
Anderschou and others (1918); Anderschou (1920); July 24, 1917 and September 5, 1919GB (London)GB 117666; GB 149533C; MUnder aeration, washing with borax or alkali carbonate, and mixing with cream of tartar, potato flour, and milk powder
Ohlhaver (1930); August 28, 1928 (DE)DE (Sande)GB 318155 (FR 680847)C; MAeration and violent mixing, with sugar and alkali bicarbonate
Marescu (1930); Maresco (1930); September 28, 1928RO (Bucharest)GB 320021 (FR 676677)C; MPhosphoric acid and ammonia, with aeration
Windesheim and Thiele (1931); Windesheim (1931); August 14, 1929 (DE)DE (Berlin)GB 347542 (FR 698316; DE 536061)CCharcoal and cholesterine (cholesterol)
Bergl (1932); jointly licensed to Bermann (1936) and Butacon Aktiengesellschaft (US) October 30, 1930 and March 20, 1931 (DE)DE (Berlin)FR 723515 (AT 143878; CH 157929); US 2053596C; MAeration in a sugar solution, under pH control with phosphates
Dinich (1935); licensed to Vogelbusch (1937; AT); licensed to Fuchs (1937; US) June 27, 1933 (HU) and November 13, 1934 (GB)HU (Budapest); CS (Mihalovse); AT (Vienna)HU 111224; GB 434249 (FR 781220; CH 182950; DK 51823; AT 149531; US 2072748)C; MPurification with formaldehyde; stepwise acclimatization to high growth temperature
Draghi (1941); March 18, 1937US (New York)US 2233251CAcetone
Knappe (1943); January 15, 1941 (DE)DE (Mettingen)FR 887077 (DE 852681)FActivation in acidified media (no other nutrients); distiller's yeast
Phrix-Werke Aktiengesellschaft (1945); April 29, 1943DE (Hamburg)FR 903788OPlasmolyzed in a concentrated sugar solution
Hubert (1946); June 16, 1944FR (Loir-et-Cher)FR 908189M; FActivation in spent sugar media with aeration; distiller's yeast
Milosavljevic (1993); September 30, 1991YU (Svetozarevo)EP 0537547CSodium carbonate and sodium bicarbonate
Simard and Bouksaim (1998); assigned to Université Laval; August 9, 1995CA (Ste.Foy, QC)US 5716653C; FTreatment with surfactants (Tween 80) and activation in nutritive media

According to Table 8, aeration and treatment with alkalis were among the most popular techniques for debittering yeast; yeast was also bleached with charcoal. A few patents on the reuse of distillery yeast for baking applications were issued in the 1940s. No major evolution in yeast debittering techniques was seen during the years that this was practiced so, in general, spent brewer's yeast was simply washed with chemicals. In general, the proposed techniques were quite simple and little interest was given to quality control or gassing power of raw materials (brewer's yeast) and the final product (debittered brewer's yeast).

Historical context

As early as 1859, many inventors proposed solutions to recycle brewer's yeast for baking applications because plenty of spent yeast was available (Gélinas 2010a). In GB, interest for recycling brewer's yeast for bakery applications may be explained by the poor quality of conventional baker's yeast available up to 1915 to 1920 (unpleasant odor, dark color, and poor keeping properties and gassing power). The cost of commercial baker's yeast was a major concern because brewer's yeast was available at a fraction of its price, one-fifth according to some inventors. In practice, it is likely that debittered brewer's yeast found relatively little use for baking compared to medicinal applications (food yeast), mainly as vitamin and protein supplements. According to Klieger (2004), yeast was “alledgely curing everything from acne to constipation” so, in the United States, Fleischmann Yeast was a very popular healthy food supplement from 1919 until the end of the 1930s when the company was fined for exaggerated health claim.

Between 1920 and 1933, alcohol prohibition in the United States might partly explain the absence of interest in patenting techniques for brewer's yeast recycling. In Germany, patenting activity on brewer's yeast recovery might be linked to shortage of raw materials for yeast manufacture, either grain or molasses, before and during the two World Wars. This situation might also be linked to the high cost of baker's yeast during that period. Until 1944, a few patents on large-scale treatments of brewer's yeast for baking applications were developed by German inventors, but these innovations were essentially the end of a long association between brewing and baking.

In a patent, Dinich (1935) proposed some explanations for the limited success of brewer's yeast for baking applications:

Attempts have been made to use brewer's yeast in the baking trade, but none of the known processes has been commercially successful. Since brewer's-yeast costs nothing and the working costs are more than counterbalanced by the value of the baker's-yeast produced, the process is a profitable one. An examination of pressed brewer's yeast with the microscope proves that this product consists of a mass of millions of living and dead cells intertwined one with another, the mass being easily spoiled even at ordinary temperatures. An investigation into the reason for this spoiling will show that brewer's yeast is not able to withstand the higher temperatures prevailing in the rising of dough, because it has been cultivated in the course of the brewing of beer throughout generations at very low temperatures. In higher temperature zones, the decomposition of dead cells also begins rapidly and the living cells, being pressed closely against the dead cells that are decaying, will be destroyed in an extremely short time by the decomposition products. Attempts to bake with brewer's yeast prove that at low temperatures, at which very active living cells are present, brewer's yeast is suitable, and what is more, it ferments more strongly than alcohol-yeast. This activity, however, weakens proportionally and even ceases with the gradual rising of temperature, the dough remaining unfermented and the bread being flat, its taste strange, often even unpleasant as the decomposition products of the brewer's yeast are not able, in the absence of the development of carbonic acid, to leave the dough.

On the long run, brewer's yeast was a poor competitor to baker's yeast. The baking industry strictly requested baker's yeast with constant quality. It was realized that brewer's yeast could not be a long-term solution for baking, just as baker's yeast could not be a long-term solution for brewing.

Basic Liquid Media

Table 9 presents patents issued after 1900 and describing alternative basic liquid sugar-rich media (others than molasses) for yeast growth for large-scale applications, not artisanal. In general, the earliest patents on basic liquid growth media resembled recipe development, close to that of artisanal sourdough-based yeast preparations described above. This was the most important subject with more than one-third of patented inventions on yeast growth media (Table 1). However, none of the proposed technologies appeared to have been a breakthrough since it was not adopted on the long term and molasses has remained the main basic medium for growing baker's yeast.

Table 9–.  Patents published between 1900 and 2009 on basic liquid media for the manufacturing of fresh baker's yeast (alternatives to molasses).
Inventor (publication y); priority dateCountry (city)Patent nr.BaseaDetailsb
  1. aA = alcohol-rich medium; C = cellulose-rich medium (wood, peat, waste sulfite liquor); G = glucose- or maltose-rich medium, such as molasses; S = starch-rich medium (cereals, tubers, and so on); W = waste food materials (fermentation dregs, whey, bread waste, and so on); O = others.

  2. bInformation on growth media preparation is given (clarified, sterile, and aeration) only when clearly mentioned in the patent specification.

Rakhmanoff (1900); April 5, 1899RU (Moscow)GB 189907142SSoda-treated corn with kvass (saccharified and fermented corn); with seed yeast
Barbet (1900); December 1, 1899 (AT)FR (Paris)GB 190001228 (AT 2778)SSaccharified maize or potatoes; clarified, sterile, and aerated
Woolner (1901); April 10, 1900    
 US (Preoria, Ill.)US 672996SMalted cereals (air-pressure)
Bauer (1900); June 22, 1900 (AT)AT-HU (HU; Raab)GB 190011760 (AT 3885; DE 130072)SAcidified starchy materials (maize, rice, or potatoes) with brewer's yeast extract, and seed yeast; sterile and aerated
Bücheler (1901); June 22, 1900DE (Weihenstephan)DE 123437SStarchy materials (potatoes) acidified with sulfuric acid
Mühlenbauanstalt und Maschinenfabrik vorm. Gebr. Seck (1902); September 22, 1900DE (Dresden)DE 132642SMalt (finely milled)
Suschny (1904, 1906); January 22, 1901AT-HU (AT; Fischamend)AT 15095; AT 22732SSaccharified (acid-treated) starchy materials
Bramsch (1902); March 11, 1901AT (Teplitz)AT 6995WPeptonized dregs from brewer's hops
Société des produits amylacés (1902, 1905); December 5, 1901FR (Paris)FR 316582; FR 350793SSaccharified starch byproducts (rice and others); pure seed; sterile
Lankow and Lankow (1903); December 8, 1901DE (Dresden)DE 140820SSaccharified rye or corn
Kruis and Firma F. Ringhoffer (1904, 1906); Kruis (1909, 1910); licensed to Goldschmidt (1910, 1912); May 22, 1902 (AT)AT-HU (AT; Prague; Taikowitz)AT 15051 (DE 173231); FR 366533 (AT 28085; DE 180594); FR 402855 (AT 47148); GB 191027845 (AT 43081; AT 51923)G; SBeet juice, saccharified potatoes, and molasses; clarified, sterile, and aerated
Lankow (1904); January 21, 1904DE (Kiel)DE 157020SPotatoes, frozen-thawed and pierced
Erdös (1909); April 22, 1905AT-HU (AT; Vienna)AT 38131SMalted corn; clarified and sterile
Nycander (1906); September 12, 1905GB (London)GB 190518393SSaccharified manioc, arrow-root, or sago flour; clarified
Sěbek (1908a, 1908b); February 26, 1906AT-HY (AT; Grosz-Popowitz, Bohemia)AT 33215; AT 33685SSugared mash (potatoes) is acidified with mineral acid; waste brewer's yeast may be used as starter; for distilleries
Mühlenbauanstalt und Maschinenfabrik vorm. Gebrüder Seck (1907); April 15, 1906DE (Dresden)DE 190144SMalt filter; easy to fix and assemble
Braunbeck (1907); November 13, 1906DE (Berlin)GB 190625595SHighly active wheat malt
Lapp (1908); January 7, 1907DE (Berlin)US 891553SPressure-treated barley (before malting)
Barbet (1910); February 6, 1909FR (Paris)FR 409040SSaccharified corn and rye; clarified, sterile, and aerated
Piot (1911); January 17, 1910FR (Nord)FR 422403SExtract from fermented grain or starchy byproducts previously seeded with leaven or pure yeast; may be aerated and supplemented with nitrogen
Goldschmidt and Kruis (1911); October 10, 1910AT-HU (AT; Taikowitz)AT 48786S; GJerusalem artichoke; may be mixed with saccharified potatoes and molasses; clarified
Piot (1912); November 7, 1910FR (Nord)FR 433841SCereals, saccharified with amylolytic molds; clarified and sterile
Menz (1913); Menz and Stiebler (1913); July 18, 1912 (CH)DE (Breslau)CH 60527 (GB 191219245; FR 447600)SGrated potatoes in water, aerated, and seeded with yeast
Verein der Spiritus-Fabrikanten in Deutschland (1914, 1916, 1919a,b,c,d,e,f,g); May 8, 1913DE (Berlin)FR 472073;
CH 72486;
DE 310461;
DE 314163;
A; SSpent wort (sugar-free) from starch, alcohol, or yeast manufacturing; clarified and aerated; may be mixed with starch-based media
  DE 314164;  
  DE 314165;  
  DE 314166;  
  DE 314330;  
  DE 314331  
Schaefer (1915); July 30, 1913DE (Frankfurt)US 1138251SMash filter-plate
Audouin (1915); February 26, 1914FR (Gard)FR 475487SMalted cereals (rye) or starchy materials
Marbach and Sailer (1915); February 27, 1914AT-HU (AT; Vienna)AT 67701SCereal-based extract; Vienna method; clarified
Macaigne (1918); December 12, 1916FR (Paris)FR 487159SStarch-based wort saccharified with amylolytic molds; clarified, sterile, and aerated
Bayer and Orla-Jensen (1919); August 16, 1917 (DK)DK (Copenhagen)FR 491891 (GB 119030)SSea-weeds and algae
Peter (1923); December 9 1917DE (Wandsbek)DE 381339SSaccharified potatoes (raw)
Vasseux (1920); January 19, 1918 (FR)FR (Saint-Mandé, Seine)FR 508953 (GB 147581; AT 104869)C; GPeat extract with molasses; clarified and aerated
Corby and Glasgow (1923, 1926); assigned to The Fleischmann Co.; March 13, 1919US (Chevy Chase, Md.)US 1475471; US 1571932S; GCereal-based mash, molasses, and inorganic nitrogen
Demuth (1923); June 27, 1919 (AT)AT (Schaftenau)DE 371349C; GSaccharified wood (sulfite-free) with molasses
Krohn (1920); priority date unknownFICA 200304CWaste sulfite liquor; aerated
Vasseux (1921); May 22, 1920FR (Saint-Mandé, Seine)FR 626665 (US 1472344)C; WCellulose-rich plant residues (fruit dregs, wine press residues, bran, straw, sawdust, seaweed)
Wagner (1922); May 9, 1921US (Brooklyn, NY)US 1434462W; GCorn steep waters with sugar syrup; sterile
Mezzadroli (1922); December 16, 1921ITFR 544636SCereal-based wort saccharified with amylolytic molds
Ransohoff (1924); assigned to The Fleischmann Co. (US; CA); licensed to The Intl. Yeast Co., Ltd. (GB); January 19, 1922 (US)US (New York)US 1722858 (CA 229401); GB 192085 (not accepted)A; S; GEthyl alcohol with cereal- or molasses-based media; yield
Dahlberg (1926); June 8, 1922 and March 5, 1925 (US)US (Denver, Colo.)GB 246002 (US 1580999; US 1581000)W; GWaste waters from sugar manufacturing, with molasses
Klein (1924a, 1924b); licensed to The Fleischmann Co. (US; CA); licensed to van Lier (NL); August 29, 1922 (AT)RO; AT (Vienna)FR 565464 (AT 103075; GB 203300; US 1722803; CA 250753; NL 13773); GB 205813 (AT 100697)W; GDifficult-to-attack media (residual slops from yeast manufacturing, with phosphates) switched with easy-to-attack media (molasses or grain); aerated
Gaux and Salmon (1924); June 19, 1923 (FR)FR (Avesnes-sur-Helpe, Nord)FR 567608 (GB 217909)W; GCasein-free whey with molasses
Wagner (1930); July 30, 1923US (Brooklyn, N.Y.)US 1784402GAcidified corn starch liquor (dextrose syrup)
Vasseux (1925); 20 November 1923FR (Saint-Mandé, Seine)FR 585990GBeet and fruit-based media
Vasseux (1925a, 1925b); January 11, 1924FR (Saint-Mandé, Seine)FR 588431; FR 597135GWaste waters from sugar manufacturing, with molasses; filtered and aerated
Balls (1927, 1930); partly assigned to Nilsson and Hixson; January 24, 1924US (Philadelphia, Pa.)US 1634348; US 1761515GSugar juice from cut, sliced, and washed cane
Eijkenskjöld (1928, 1929, 1930); assigned to Aktiebolaget Bästa; licensed to Vereinigte Mautner Markhof'sche Presshefe Fabriken und Aktiengesellschaft Ignaz Kuffner & Jacob Kuffner für Brauerei, Spiritus-und Presshefefabrikation (1931; AT); March 28, 1925; June 14, 1926; March 14, 1928 (SE)SE (Stockholm)SE 64498 (US 1680043; US 1881557; DE 580339; FR 614037; AT 118863); SE 66792 (US 1703272; DE 617670; AT 125163); US 1757568 (DE 610657; CA 300529)CWaste sulfite liquor (wood)
Campbell (1926); July 18, 1925IE (Monasterevan)US 1581918SGrain malting equipment
Szpilfogel (1928); June 24, 1926 (PL)PLFR 636481ONonsugared wort containing only nitrogen and phosphorus
Hägglund (1929); assigned to Holzhydrolyse Aktiengesellschaft; December 14, 1927 (DE)FI (Abo)GB 302313 (DE 526527; FR 665972; .US 1818618)CHydrolyzed cellulose (wood)
Selbi (1928); January 13, 1928 (FR)CH (Geneva)FR 647879AAlcohol recovered from outlet air or growth medium for yeast manufacturing
Selbi (1929, 1931); Metzl (1930); January 19, 1928 (FR)CH (Geneva)FR 661225 (GB 304314; CA 297117; CH 138306); FR 709458WSpent media (vinasse) from distilleries, sugar factories, or yeast factories; sterile
Mayer (1930); February 28, 1928IT (Darfo)DE 489167SDiastase-rich malt extract
Langfeldt (1929); June 9, 1928 (NO)NO (Oslo)FR 658099 (CH 139787; DE 543774; GB 311979; AT 122455; US 1834788)SCassava
Jalowetz and Hamburg (1931); February 15, 1930AT (Vienna)AT 122955W; GSpent brewer’ yeast media with sugar (molasses, malt, and so on)
Collette (1932, 1933); April 1, 1931FR (Nord)FR 729980; FR 750998GRaw beet juice, concentrated
Boulard (1934); May 8, 1933FR (Paris)FR 769020GSugar
Wroten (1938); July 20, 1933US (Baltimore, Md.)US 2106784SStarch, with malt or amylase
Seidel (1938); March 31, 1936 (DE)DE (Munich)FR 833029 (GB 505940; US 2232737)AAlcohol recovered from outlet air (yeast manufacturing)
Schultz and Atkin (1940); Schultz and others (1943); assigned to Standard Brands Inc.; June 9, 1938US (New York)US 2202356; US 2311418GMaltose-rich media, with small amounts of dextrose or oxygen
Jackson, and Arthur Guinness, Son and Co. Limited (1939); July 14, 1938GB (London)GB 511394WHydrolyzed milk or whey with galactose- and glucose-fermenting yeast
Deloffre (1942, 1961); assigned to Fermzymetera Société anonyme Holding (1956; 1959; DK and DE); licensed to Effront (1961; AT); January 22, 1941 (AU) and October 21, 1960 (LU)AU (Toorak); LU; CH (Geneva)AU 114926 (FR 885959; GB 553908; US 2367931; DK 82072; DE 971590; CA 420018); AT 218451; LU 39319 (FR 1278761; US 3120473; GB 983491; AT 269037; DE 1417562; ES 271135; BE 606608; CA 671312)W; GSpent yeast growth media (alcohol-rich), with molasses
Jeffreys (1948a, 1948b, 1949); assigned to N. Littell; November 3, 1941US (Salem, Va.)US 2440545; US 2440546; US 2480738SConcentrated and saccharified granular substances (broken kernels or bran), coated with seed yeast
Södeström and Rost (1945); November 22, 1941 (SE)SE (Spranga)US 2381230C; GWaste sulfite liquor (paper manufacturing), with molasses
Boinot and Gautier (1950); Boinot and Gourguechon (1952); assigned to Les Usines de Melle; March 27 and July 7, 1947FR (Melle, Poitou-Charentes)US 2529131 (FR 1004269); FR 1005355
(CA 530548)
W; GSpent media (distillery, wine, molasses, sugar beet, cider, starch residues)
Kirnbauer (1950); assigned to Vereinigte Mautner Markhof'sche Presshefe Fabriken (1950); May 16, 1947 (AT)AT (Vienna)AT 165437 (CH 269170; GB 648550)W; GSpent yeast growth media (de-alcoholized), with molasses
Lesaffre & Cie (1952); January 28, 1950FR (Marcq en Baroeul, Nord)FR 1009496 (GB 694786; CH 288404)W; GSpent yeast growth medium is pH-adjusted above the isoelectric point of the coloring matter (3.7 to 4.3); to replace 25% molasses, color (lighter), gassing power, and keeping properties
Bernhauer (1955); Bernhauer and Becher (1955); assigned to Aschaffenburger Zellstoffwerke A.G.; September 8, 1950DE (Lorsch)US 2698827; US 2698828CWaste sulfite liquor
Sellers and others (1969); assigned to Chas. Pfizer & Co. Inc. (1966); November 13, 1963 (US)US (New York)US 3461035 (GB 1045195)W; GCitric acid spent fermentation media, with a mixture of beet and blackstrap molasses
Moebus and Kiesbye (1975a, 1975b, 1976, 1977); Moebus and others (1978, 1979); January 24, 1974DE (Kiel)DE 2403306; DE 2410349; DE 2500323; DE 2610919; DE 2656663; DE 2752485 (GB 1542750)W; SWhey (fermented with lactic acid bacteria) with starch-containing media (amylase-treated wheat flour)
Ogawa and others (1978); assigned to Nippon Beet Sugar Mfg.; December 10, 1976JP (Tokyo)JP 53072888W; GBeet processing wastewater, with molasses
Yanagisawa and others (1977); assigned to Oriental Yeast Co., Ltd., and Matsutani Kagaku Kogyo; April 22, 1977JP (Tokyo)JP 52130977STapioca saccharified with alpha-amylase
Katou and others (1977); assigned to Kanegafuchi Chemical Ind.; September 24, 1977JP (Osaka)JP 52114085WSpent yeast growth media
Yoshizawa and others (1979); assigned to Kokuzeicho Japan, and Kibun KK; October 28, 1977JP (Showamachi)JP 54064685WSpent waters from distilleries
Ogawa and others (1979); assigned to Nippon Beet Sugar Mfg.; October 31, 1977JP (Tokyo)JP 54129181GRaw sugar, with molasses
Stineman and others (1980); assigned to The Kroger Co.; November 30, 1978US (Cincinnati, Ohio)US 4192918WAcid whey treated with β-galactosidase or other means; reduced pollution
B. Wendeln jr. GmbH (1987); Schubert and others (1987); January 20, 1986DE (Oldenburg)EP 0229979 (DK 29987)WLeftover bread treated with enzymes
Felch (1988, 2000); assigned to Müller-Brot GmbH; July 15, 1986DE (Freising)DE 3623896; DE 19835269WLeftover bread treated with enzymes
Babel and others (1990); assigned to Akademie der Wissenschaften der DDR; August 23, 1988DD (Berlin)DD 275071A; GIsopropanol and molasses
Bernstein (1990); assigned to Krupp Industrietechnik; September 16, 1988DE (Duisberg)DE 3831497S; G; WHydrolyzed starch with molasses (0% to 20%); spent media is reused to reduce waste water
Abramov and others (1997); assigned to Prikaspijskij institut biologicheskikh; April 29, 1992RURU 2084519GGeothermal water with molasses
Vinetskij and others (1997); assigned to Gosudarstvennyj nauchno-issledovatel'skij institut; December 17, 1992RURU 2073711WWhey treated with enzyme or mold culture
Tuljakova and others (1998); assigned to Tovarishchestvo s ogranichennoj otvetstvennost’ju “Tekhnol-Bio”; August 30, 1994RURU 2103347WLeftover bread
Meuser (1997); assigned to Dietrich Reimelt KG, and Müller-Brot GmbH; August 2, 1996DE (Berlin)DE 19631180 (AU 733776; EP 0821877)WLeftover bread treated with enzymes
Moriya and others (1998); assigned to Nippon Beet Sugar Mfg. Co., Ltd; November 6, 1996JP (Tokyo)JP 10136975GBeet sugar waste waters with molasses
Baturina and others (1998), assigned to Aktsionernoe obshchestvo zakrytogo tipa “INTEKO”; June 19, 1997RURU 2113470SStarch saccharified with enzymes
Ando and Fukuoka (1999); assigned to Oriental Yeast Co. Ltd, and Soken Co. Ltd; May 8, 1998JP (Tokyo)JP 11318323GOrganically grown sugar cane or beet
Shima and others (2004); assigned to Natl. Food Research Inst.; March 31, 2003JPJP 2004298139O; GSynthetic medium with molasses extract
Pashchenko and others (2005); assigned to Voronezhskaja gosudarstvennaja tekhnologicheskaja akademija; June 11, 2004RU (Voronezh)RU 2251569SSaccharified and gelatinized flour (barley, amaranth, pea)
Bell and others (2009); assigned to Microbiogen Pty Ltd; June 27, 2008AU (Sydney)WO 2009155633CLignocellulosic hydrolysate containing xylose and other C5 compounds (cane trash; corn leaves and stalks), using specific yeast strains

In the 1920s, interest for starch-based media was superseded by waste materials from spent fermentation media (brewing, distilling, and yeast), cheese manufacturing (whey), or waste waters from corn starch or sugar processing. To a lesser extent, residues from the wood industry were also considered as cheap alternatives to molasses, especially between 1915 and 1929.

Besides starch and molasses, the following growth media were popular: waste waters from sugar manufacturing or pure sugar (8 patents), spent baker's yeast or miscellaneous fermentation growth media (8 patents), paper manufacturing byproducts, such as waste sulfite liquor (5 patents), bread wastes (4 patents), cheese-manufacturing byproducts, such as whey (3 patents), corn starch, or steep liquor (2 patents), and wood (2 patents). The following were also proposed: peat, Jerusalem artichoke, sea weeds, isopropanol, and synthetic media.

While the reuse of yeast fermentation media was often proposed, special attention may be paid to a patent granted to Chas. Pfizer & Co. Inc. describing the reuse of spent fermentation media for citric acid (Sellers and others 1969). Surprisingly, partial recovery of such spent fermentation media did not appear to be successful and was not adopted as a partial substitute for molasses for growing baker's yeast. For example, at the completion of the process, yeast growth media contains about 5% solids, which means that much waste water is produced.

In essence, patents on basic liquid media mainly addressed the following concerns on the quality of commercial baker's yeast: (1) cost through the selection of cheap raw materials and improved yield of fermentable sugar and, in only a few cases, (2) yeast gassing power and appearance (color). Indeed, molasses was not a ready-to-use ingredient because baker's yeast manufacturers had to develop themselves techniques for cleaning this sugar by-product. These questions are treated in the following section. In essence, long-term review of the patenting activity shows that alternative liquid media are still looked for by this industry to replace molasses (Table 1).

Historical context

Baker's yeast cannot grow on starch that must be degraded prior to fermentation. In the 19th century, saccharified grain was the main nutrient source for baker's yeast, saccharification being a process where starch is converted into fermentable sugars. Yeast was generally grown on media prepared from crushed grain (corn, occasionally rye) previously cooked and saccharified with finely ground malted grain (Jago and Jago 1911; Hart 1914; Allen 1926). About 50% malt of the weight of grain developed sufficient amylase and protease. Rich in amines and amides, rootlets (small grain roots) were also used as supplementary protease sources. Alternative solutions were needed because malt was very costly and did not give a constant yeast yield (Effront 1917). In addition, during the First World War (1914 to 1918), grain was prohibitive and was necessary for human consumption (Frey 1930). After mashing for about 1 h at 50 to 55 °C (proteolysis) and 65 °C for several hours (starch breakdown), concentrated mash was sterilized, filtered, and fermented for 10 to 12 h under aeration at 30 °C with a pure culture of yeast (2.3% of the grain used). Yeast was separated from the wort with centrifugal machines, to yield compressed yeast containing about 75% moisture.

As mentioned, ways were searched to get the highest yeast yield possible using the easiest manufacturing process, and at the lowest cost possible. Optimization of starch-degrading processes was very popular, through enzyme source or malting equipment. According to the U.S. version of a patent by Effront and Boidin (1916), grain was not a cheap ingredient and it was a matter of time before it was replaced by molasses, when better technology allowed its use. These authors described some of the limits of using grain for yeast production:

In the manufacture of pressed yeast, a very large proportion of malt has heretofore been necessary; thus 10 times more diastase has been introduced into the mash than the quantity required for the saccharification. The use of this excess of malt is, however, justified on account of the necessity of providing the yeast with proper nutriment, that is to say, with nitrogen in the form of amids that is not found in sufficient quantity in nongerminated cereals. The result of the employment of large proportions of malt is to raise the cost price of the pressed yeast and to cause considerable loss of fermentable materials.

In the scientific literature, several papers have also been published on growth media, as alternatives to molasses for baker's yeast manufacture. Especially when molasses was not locally available, baker's yeast manufacturing was seen as a potential market for adding value to sugar- or starch-based foods, such as dates (Khan and others 1995; Alemzadeh and Vosoughi 2002; Al-Jasass and others 2010), millet (Ejiofor and others 1996), and cassava (Aransiola and others 2006). In addition, cheap agro-industrial waste products were also proposed to supplement or replace molasses, including cheese whey permeate (Champagne and others 1989; Ferrari and others 2001), wastes of wheat and potato starch (Lotz and others 1991), orange peel (Plessas and others 2006), and corn steep liquor (Spigno and others 2009).

Decrease in the quality and variability of molasses over the years would explain why alternative media have continuously been explored. The multiple applications of molasses in the food industry and elsewhere (feeds, bioethanol, and others) also create much pressure on costs and availability (Rüter 1977; Sinda and Parkkinen 1979; van Dam 1986; Cofalec 2006). In addition, new baker's yeast strains capable of using all molasses constituents or growing on alternative media have been searched and patented (Gélinas 2009).

Molasses Treatment

Table 10 presents 53 patents issued between 1900 and 2009 on processes and equipment for treating molasses. Most of these inventions were developed between 1920 and 1934 and were based on the chemical purification with acids, coagulants, or centrifugation. According to Walter (1953), mechanical clarifying of crude molasses revolutionized molasses clarification in yeast plants, as first described in a patent filed in 1931 by Ramesohl & Schmidt Aktiengesellschaft (later renamed Westfalia Separator AG) in Oelde, Germany.

Table 10–.  Patents published between 1900 and 2009 on molasses treatment for baker's yeast manufacturing.
Inventor (publication y); priority dateCountry (city)Patent nr.TreatmentaDetailsb
  1. aC = chemical treatment (including flocculation with alum and other precipitants); F = fermentation; M = mechanical treatment (no chemicals); O = others.

  2. bSugar concentration may be expressed according to different scales: Balling (°B), Brix (°Bx), or Baumé (°Bé). The Balling and Brix scales are almost identical and correspond to % sugar in water (Ball 2006); 1 °Bé approximately equals to 1.75°Bx based on the following formula: °Bx = (1.905) °Bé− 1.6.

  3. cBreakthrough.

Fuhrmann (1900); licensed to Kafka (1900); August 6, 1898 (DE)AT-HU (AT; Brüun; Olmütz)DE 108334 (AT 1212; GB 189915451)CDiluted, clarified with alum, and heated (70 °C)
Bramsch (1900); January 12, 1899 (AT)AT (Teplitz)AT 967 (GB 190008305)CDiluted, clarified with lignite, boiled, and filtered
Collette and Boidin (1902); February 1, 1902FR (Séchin, Nord)FR 318297CTreated with phosphoric acid (nutrient), heated, and filtered to eliminate yeast inhibitors (minerals and heavy metals); for distilleries
Meunier (1907); March 27, 1906FR (Seine)FR 373758CDiluted (20 °Bé), heated (60 °C), clarified with precipitants, and filtered; cold sterilization; for distilleries
vel Bróg and Cuker (1912); November 15, 1911AT-HU (AT)FR 436401CDiluted (20 °Bé), bleached, and sterilized with sulfuric acid, supplemented with nutrients, boiled in a solution of potassium permanganate or chromic acid, and filtered
Roth (1914); April 2, 1913 (AT)AT-HU (AT; Olmütz)FR 470925 (US 1170110; AT 89147; DE 313380)CDiluted (35 °B), acidified with sulfuric acid to precipitate finely divided matter, heated, diluted (20 °B), acidified, aerated, and slowly filtered
Murmann (1922); December 15, 1917AT-HU (AT; Pilsen)AT 88647ODiluted, moderately heated, and treated with an electric current
Sailer (1922); September 4, 1919CS (Senica)DE 355596MDiluted and cleaned with a double diffusion system
Wohl (1921); licensed to The Fleischmann Co. (US); licensed to van Lier (NL); April 7, 1920 (DE)DanzigGB 169504 (CH 97046; DE 402250; AT 100442; SE 54534; US 1449134; NL 12996)CWithout heating, concentrated molasses (30 to 40 °Bx) is sterilized with 2% sulfuric acid and supplemented with phosphates (to form assimilable phosphoric acid)
Gilmour (1922); February 17, 1921GB (Belfast)GB 180043CDiluted (20 to 25 °B), highly acidified, clarified with charcoal and malt, boiled, filtered, supplemented with ammonium salts, and filtered; to eliminate grey color of the mash; fermented at 2.6 to 3.6 °B
Dameran (1922); assigned to Dresdner Presshefen-und Kornspiritus-Fabrik sonst J. L. Bramsch (1923); December 31, 1921 (DE)DE (Dresden)FR 551220 (DE 420172; SE 56900)CDiluted (10 to 20 °B), strongly acidified at a low temperature (below 62 °C), and filtered; further acidification during yeast growth is avoided
Batist and Drexler (1924); assigned to Vereinigte Mautner'sche Presshefe-Fabriken Gesellschaft, m.b.H.(1924); April 29, 1922 (AT)AT (Vienna)GB 196926 (FR 565548; AT 99496)CDiluted (18 °B), boiled, clarified with superphosphate (acid-treated phosphate) under aeration, mixed with alkali (ammonia), and sediment is eliminated
Dresdner Presshefen- & Kornspiritus-Fabrik sonst J. L. Bramsch (1926); July 4, 1922DE (Dresden)DE 424168CAcidified, without decantation and heating; diluted, brought to 20 to 50 °C, and filtered over moistened sand
Kusserow (1926, 1927); October 29, 1922 (DE)DE (Sachsenhausen); US (Oakland, Calif.)US 1580500; DE 439498CWithout heating, molasses is diluted (20 °B), acidified with strong acids, decolorized with sodium thiosulfate, filtered with a filter press, and diluted (3 to 6 °B)
Hamburger and Kaesz (1924); licensed to Standard Brands Inc. (US); December 23, 1922 (CS)CS (Freudenthal); AT-HU (AT)GB 209034 (FR 589757; DK 36049; CH 109470; AT 105789; SE 59099; US 1770402)CDiluted (18 °B), acidified, heated, clarified with large amounts of alkali silicates or aluminum salts, and drawn
Murmann (1924); assigned to Hamburger and Kaesz; December 24, 1922 (DE)CS (Pilsen)DE 403376CDiluted and treated with chlorine dioxide (gas)
Roth (1926); April 21, 1923 (CS)CSCS 19713CDiluted, treated with lime and sulfuric acid, and clarified with superphosphate
Hoffman and others (1928); assigned to The Fleischmann Co.; May 8, 1923US (New York)US 1687561CDiluted (3 to 5 x), supplemented with sodium or potassium silicate (pH 7.7 to 12), boiled, and filtered; cane molasses
Jörgensen and Kalhauge (1924); March 14, 1924 (GB)DK (Copenhagen)FR 581738 (GB 228734)C; FDiluted, treated with superphosphate and sulfuric acid, boiled under slight aeration, treated with lime, separated, cooled, and treated with lactic acid bacteria (to limit acid treatment and improve clarification); fermented at 0.5 to 0.8 °B
Drexler (1925); assigned to Vereinigte Mautner'sche Presshefe-Fabriken, G. m.b.H. (1926); May 30, 1924 (AT)AT (Vienna)AT 101649 (DE 101649; GB 234843; FR 601788)C; FWithout heating, molasses is diluted (20 °B), subjected to lactic fermentation, and pressed through a filter press on which chalk and talcum powder are deposited; to avoid vitamin destruction
Corby and others (1928); Ransohoff (1928); assigned to The Fleischmann Co.; May 11, 1925US (New York)US 1667928; US 1688831CDiluted (15 to 20 °B), heated, mixed with an alkali (sodium bicarbonate), and phosphorus-containing substance (phosphoric acid or ammonium phosphate), heated, and filtered; cane molasses
Kusserow (1927); October 29, 1925US (Oakland, Calif.)US 1642929C; FDiluted (25 °B), treated with alkali (to prevent growth of wild yeast), and fermented with lactic acid bacteria and molasses bacterial contaminants (to decompose colloids), heated, and decanted
Aktieselskabet Dansk Gaerings-Industri (1928); January 21, 1927 (AT)DK (Copenhagen)AT 11547 (CH 135465; FR 647492; GB 283970; DK 39844)C; FDiluted, acidified with hydrochloric acid, seeded with lactic acid bacteria and betain-assimilating bacteria, left for 8 to 10 h at 20 to 45 °C, diluted, supplemented with clarifying agents (tannin, barium aluminate) and alkalis, and filtered
Simmer (1930); assigned to Aktieselskabet Dansk Gaerings-Industri (1928); January 21, 1927 (AT)PL (Lemberg); DK (Copenhagen)AT 124556 (CH 135203; FR 647493; GB 283969; US 1774406)CTreated with barium chloride or hydrochloric acid instead of sulfuric acid that accumulates in waste waters
Savary (1929); November 4, 1927FR (Seine)FR 656335CDiluted, acidified with phosphate, treated with lime, filtered, and treated at 80 to 85 °C with superphosphate
Fermenta A.G. (1929); January 18, 1928YUYU 5798CSterilized with highly concentrated sulfuric acid and supplemented with ammonium salts
Wooldridge and Clark (1929); March 6, 1928GB (London)GB 312705CDiluted (10 °Bé), passed through a filter press coated with a filter aid (Celite), allowed to percolate through precipitated alumina or bauxite, and pressed
Bennett and Peake (1932); assigned to The Distillers Co. Limited; licensed to Standard Brands Inc. (US); June 25 1928 (GB)GB (Edinburgh)GB 319641 (FR 677228; US 1860832)CDiluted (4x), heated, diluted (1x), and mixed with large quantities of an absorbent (ground nut cake or calcium carbonate) and a protein precipitant (tannin)
Norddeutsche Hefeindustrie Aktiengesellschaft (1933); July 7, 1928DE (Berlin)DE 590209 (NO 46780)CClarified without superphosphate to avoid phosphoric acid losses
Božović (1930); October 26, 1929YUYU 7322CTreated with oxalic acid; diammonium phosphate is used instead of superphosphate
M. Fischl's Söhne and Rosenberg (1931); March 14, 1930AT (Vienna)AT 125965 (DE 603668)CWithout heating, nondiluted or slightly diluted molasses (30 °Bé) is mixed with adsorbents, such as diatomaceous earth, bauxite, and clay-type materials, aerated in an acidic solution, and sterilized
Thompson and Hinchley (1931); June 2, 1930 (GB)GB (London)GB 356703 (FR 715785; DK 47062; DE 599497; AT 136363; US 1933830)O; CDiluted with acidulated water (15% sugar), treated with an electric current (until 60% bleaching), filtered, and neutralized with an alkali
Stich (1933); assigned to Verband der ćsl. Presshefefabriken; June 23, 1930DE (Mannheim)CS 42904CMixed with precipitant, and centrifuged; might be identical to the following entry
Bergedorfer Eisenwerk Aktiengesellschaft Astra-Werke (1931); September 27, 1930 (DE)DE (Hamburg)FR 715152CMixed with chemicals (clarifiers), heated, and centrifuged (continuous)
Nowowilejska Fabryka Droźdźy Spólka z organiczona odpowiedzialnościa (1933); December 6, 1930PLPL 18722CDiluted, clarified at 85 °C with superphosphate, and separated
Ramesohl & Schmidt Aktiengesellschaft (1932); February 18, 1931 (DE)cDE (Oelde)GB 369148 (AT 136829; FR 723013)MWithout heating or chemical treatment, molasses is diluted and centrifuged (continuous with specific equipment); a first
Ramesohl & Schmidt Aktiengesellschaft (1940, 1942); March 18 and May 6, 1931 (DE)cDE (Oelde)DE 688764; DE 716927MWithout chemicals and in continuous, molasses is heat-sterilized, diluted (20 to 60 °B), and centrifuged, with 8 collecting vats between centrifuges
Lindenmeyer & Co. (1934); November 20, 1931DE (Heilbronn)DE 602426MWithout chemicals, molasses is slightly diluted, heat-sterilized, and filtered on layer filters (asbestos and others)
Ramesohl & Schmidt Aktiengesellschaft (1938); June 24, 1932 (DE)cDE (Oelde)DE 668085CPrior to centrifugation, acid is added to neutralize molasses
Naamlooze Vennootschap Industrieele Maatschappij Voorheen Noury and van der Lande (1933); June 17, 1933NL (Deventer)FR 757125 (GB 405875)CDiluted (2x), gradually supplemented with acids or alkalis to neutral or slightly acidic pH, centrifuged, and heated
Aktiebolaget Separator (1935); June 19, 1935SE (Stockholm)FR 791430MContinuously fractionated with a separator to eliminate the sludge and only the purest fraction is kept
Mead (1937); assigned to Natl. Grain Yeast Corp.; April 27, 1936US (Bloomfield, N.J.)US 2075127CDiluted with water (1 to 3x), mixed with pyrophosphate (instead of orthophosphate), heat-sterilized, and filtered
Aktiebolaget Separator (1939); February 27 and December 23, 1937cSE (Stockholm)GB 509347MDiluted and clarified in a series of centrifuges that continuously or intermittently discharge solid matter
Steinacker (1940); assigned to Ramesohl & Schmidt Aktiengesellschaft (1938); assigned to Westfalia Separator AG (1943); May 1, 1937DE (Oelde)GB 492255 (FR 862281; US 2187990; DE 732778)MSlightly diluted (40 to 50 °B), slowly centrifuged to eliminate highly soluble material, diluted again (15 to 25 °B), and centrifuged at a higher speed to eliminate less soluble and very fine particles
Bergedorfer Eisenwerk A.G. Astra-Werke (1941); licensed to Aktiebolaget Separator; August 20, 1938 (DE)cDE (Hamburg)GB 531931MSterilized with heat exchanger equipment (continuous)
Buhrig and Harff (1943); assigned to Standard Brands Inc. (1943); October 18, 1940US (Mount Vernon, N.Y.)US 2337641 (GB 551428)MDiluted, pH-adjusted (5), heat-sterilized, diluted, mixed with air, settled for 10 to 12 h, and centrifuged
Aktiebolaget Separator (1944); October 3, 1942 (SE)SE (Stockholm)GB 567959MWashed with a centrifugal separator with reduced losses
Svenska Jästfabriks Aktiebolaget (1946); September 29, 1944 (SE)SE (Stockholm)FR 916576 (GB 627830)MBlend of molasses from several storage tanks equipped with mixing devices; improved and constant yield
Rosenqvist (1948); October 5, 1945 (SE)SE (Rorebro)FR 934939 (GB 632665)MContinuous, molasses is rapidly heat-sterilized with very vigorous stirring, cooled, and centrifuged; to reduce nutrients losses
Patentauswertung Vogelbusch Gesellschaft m.b.H. (1961); October 3, 1958AT (Vienna)AT 214881MYeast is fed with cold-clarified molasses (42 °B) representing 10% to 25% of the total medium; less spent waters than standard clarification of molasses (30 °B)
Esawa and others (1976); assigned to Oriental Yeast Co. Ltd.; December 27, 1974JP (Tokyo)JP 51079780CMixed with a hydrophilic organic solvent, clarified, pH-adjusted (5), and clarified
Ripka (1983); assigned to Nabisco Brands, Inc.; July 23, 1981US (Huntington, Conn.)US 4379845MDiluted (50 to 70 °Bx), desludged in a screen-type or centrifugal-type unit, diluted (20 to 50 °Bx), and sterilized through a series of ultrafiltration units; to avoid sterilization, to give a purer growth medium, to improve yield, color, odor, and gassing power, and to reduce the BOD loading of the effluent
Hamamoto and others (1986); assigned to Shokuhin Sangyo Maku Riyou Gij; September 28, 1984JPJP 61081777MHeated (50 to 80 °C) and membrane-filtered (0.1 to 5 microns)
Chiu and Kirk (1991); assigned to Deutsche Hefewerke G.m.b.H.; November 8, 1989 (DE)DE (Hamburg)DE 3937126
(EP 426973; CA 2029403)
MDiluted (10% to 70%) and treated with ion-exchangers (weakly acidic cationic); to avoid the use of sulfuric acid
Brewer (1992); assigned to Applied Membranes Systems Pty. Ltd.; November 9, 1990 (AU)AU (Bundaberg)WO 9208810 (US 5454952)MDiluted (50 °Bx) and ultra-filtered; to yield low potassium molasses that would be less inhibitory to yeast

In the early days of the use of molasses by the yeast industry, inventors first proposed chemical treatments to clarify molasses. However, these processes were long, complicated, expensive, and involved high levels of energy (steam and cooling water) and large vessels to allow proper sedimentation. Four chemical processes were generally used: (1) with sulfuric acid, with boiling (the most popular), (2) with alkaline compounds such as lime and others, with boiling, (3) under neutral conditions, with boiling, and (4) under highly acidic conditions, without boiling. In general, diluted molasses was first acidified with mineral acid or by the action of lactic acid bacteria with a small amount of malt; this solution was then boiled by steam to sterilize it, cooled and, after the sedimentation of the dark mud, the clear solution was diluted to the desired concentration and acidity. For example, filtration of diluted molasses over sand was proposed to expedite its clarification.

Historical context

As already mentioned, grain extracts produced from malted grain were the basic growth medium in the beginnings of industrial baker's yeast manufacturing. However, its preparation (saccharification) involved several steps and raw materials were quite expensive. Inventors in the fermentation industry soon became interested in finding applications for easy-to-ferment materials, such as crystallizable sugar occurring in plants. However, refined sugar was too expensive and molasses, its cheapest and most abundant byproduct, was considered instead. By the end of the 19th century, Germany was a major beet sugar producer and exporter so large amounts of molasses were available for various industrial applications (Benninga 1990). In comparison, sugar production was much smaller in the United States until about 1920.

After 1882, patents mentioned the use of molasses for growing yeast (Gélinas 2010a). Within about 40 y, by 1920, molasses had replaced starch-based ingredients saccharified with germinated cereals (endogenous enzymes), microorganisms, or pure enzymes (Table 10). In some patents, issued after 1920, molasses was partly added to supplement basic growth media prepared from saccharified starch. According to Bauer (1925), yield of pressed yeast increased much by fermenting molasses with the aeration process (70% weight basis) compared to grain processed with the Vienna process (10% to 12%). However, several inventors complained that the appearance (odor, color) and gassing power of molasses-grown yeast was inferior to that from starch-based media.

In fact, the following problems had to be solved before molasses became a satisfactory ingredient for baker's yeast production around 1935 to 1940:

  • 1Standardized nutritive composition. Before its use by the yeast industry, molasses was generally sold for the preparation of cattle food and to some alcoholic distillation operations. However, the yeast industry was the strictest on quality aspects of molasses, including sugar concentration (saccharose), pH, and sulfur dioxide content (Olbrich 1963). Molasses has highly variable composition depending on origin; it must be considerably diluted (about 3x) and freed from suspended materials, such as iron, sulfur dioxide, tannins, dextrins, gums, pigments, clay, aluminum, and anything that inhibits yeast growth. Beet molasses was preferred to cane molasses because it was easier to process, so the latter was mainly used by North American yeast manufacturers (Olbrich 1963).
  • 2Clarification. Molasses contains many substances that darken and impart an unpleasant flavor to the yeast paste, so the latter may be unsuitable for bread applications. This subject was extensively addressed in the patent literature, but not in scientific publications. For example, the advent of continuous centrifugation revolutionized molasses cleaning procedures. A thorough account of early techniques on molasses clarification is available from Irvin (1954). These matters have also been addressed by Sinda and Parkkinen (1979).
  • 3Infection. In processes applied in the 1920s, some of the bacteria were not destroyed by acidification or heating at high temperatures, and this caused infection of the yeast growth media and, in the compressed state, yeast products spoiled very rapidly.


Table 11 presents patents on nitrogen sources for yeast manufacturing; most of these ingredients are of plant origin. Several types of cheap sources of organic nitrogen were proposed to supplement grain or molasses, including cottonseed, cereal germs, pulses, and peanut feed cake. Animal products, such as milk or whey have also been mentioned, as well as several types of animal wastes.

Table 11–.  Patents published between 1900 and 2009 on sources of nitrogen for the manufacturing of fresh baker's yeast.
Inventor (publication y); priority dateCountry (city)Patent nr.OriginaDetails
  1. aA = animal byproducts (including milk, eggs, and waste materials); I = inorganic or synthetic; P = plant byproducts; Y = yeast.

Hatschek (1900); December 22, 1899GB (Putney)GB 189925418 (AT 4261)YBrewer's yeast extract; with molasses or sugar sources; sterile and aerated; yield
Bramsch (1900); April 27, 1900AT (Teplitz)AT 2481 (GB 190008306)PExtract of acid-treated linseed cake (nitrogen source), to supplement molasses; alternative to animal charcoal; cost, color (white), gassing power, and keeping properties
Kues (1903); licensed to Wenck (1907); May 28, 1902 (AT)AT (Vienna); DE (Berlin)AT 14061 (DE 158655); DE 186163YBrewer's yeast extract
Stang (1902); July 3, 1902DE (Berlin)GB 190214852 (DK 5759)POil cake meal (lupine seeds) peptonized with barley malt; with molasses; yield
Verein der Spiritus-Fabrikanten in Deutschland (1904); July 14, 1903DE (Berlin)DE 149538PDistillery residues (dregs) peptonized with yeast
Effront (1905); January 13, 1904BE (Brussels)AT 21256PPeptonized plant extract
Maschinenbau-Aktiengesellschaft Golzern-Grimma (1904); May 13, 1904DE (Grimma)FR 343133YInactive yeast with mineral salts; for cereal-based media
Blumer (1907); July 25, 1906US (Peekskill, N.Y.)US 855276PPeptonized cottonseed meal (extract); with molasses; sterile and aerated; yield and gassing power (bottom yeast)
Paul and Remington (1907); December 15, 1906GB (Ipswich)GB 190628695PGerm extract from cereals; for brewer's yeast
Verein der Spiritus-Fabrikanten in Deutschland (1911); March 10, 1910DE (Berlin)DE 136486YInactivated brewer's yeast; for distilleries
Effront and Boidin (1911); February 15, 1911 (BE)BE (Brussels); FR (Seclin, Nord)FR 433119 (GB 191119379; AT 54820; US 1176528)PGrain peptonized with proteolytic bacteria; substitute to grain malt; yield
Hamburger & Co. GmbH (1914); April 30, 1913AT-HU (AT; Vienna)AT 66487ASkimmed milk, enzyme-treated or not
Fränkel and Fischl (1919); May 5 1916 (AT)AT (Vienna)AT 77658 (FR 514353)Y; P; AExtract from yeast, plant germ, or egg yolk; for alcohol production
Stagner (1922, 1923a, 1923b); Gallagher (1922); assigned to Natl. Retarder Co.; July 6, 1918US (Pittsburgh, PA; Oak Park, Ill.)US 1425035; US 1457319; US 1457320; US 1431448AHydrolyzed animal byproducts, such as hair, skin, hides, nails, wool, feathers, collagen, ligaments, or chrome-free tanned leather; for cereal-based media; cost
Effront (1919); May 26, 1919 (BE)BE (Brussels)FR 497344 (GB 160496; AT 93845; DE 375708)PHydrolyzed peanut and soya feed cakes; for cereal-based media or molasses; yield
Bacon (1925); assigned to The Fleischmann Co. (1924); July 31, 1919US (Pittsburgh, Pa.)GB 225252 (US 1532858)P; AVitamin-rich materials (rice polish or milk solids); to supplement inorganic nitrogen; yield
Wahl (1921); February 18, 1920US (Chicago, Ill)US 1379294PCereals gradually peptonized with bacterial lactic acid, to improve solubility of nitrogen and minerals; for cereal-based media
Wesener (1925); September 16, 1921US (Chicago, Ill)US 1526032PExtract from steep water from corn or other grain mixed with calcium (di- or tricalcium phosphate); yield
Hoffman and others (1923); assigned to Ward Baking Co. (1923); March 22, 1922 (US)US (New York)GB 195347 (FR 558024; CA 228600; CH 105698; SE 56901; US 1575761)PDefatted and peptonized rice polishings or cereal germ; to be mixed with ammonium chloride and calcium carbonate; yield, cost, and gassing power
Pollak (1924); May 16, 1922 (DE)CS; AT (Vienna)GB 197935 (US 1558627; FR 565074)PPlant proteins (such as legumes, cereals) peptonized by step-wise acidification; yield and gassing power
Grognot and Beck (1923); December 23, 1922FR (Rhône)FR 560335PDefatted peanut feed cake (hydrolyzed); to be mixed with ammonium sulfate and molasses
Hamburger (1925); assigned to Mellemeuropaeisk Patent-Financierings-Selskab Aktieselskab (1925); February 28, 1924 (CS)CS (Freudenthal); DK (Copenhagen)GB 230049 (AT 100708; CA 258494)AExtract of animal waste (such as fish preserve, dried blood, horn meal, powdered leather)
Epstein (1932); October 5, 1925US (Chicago, Ill.)US 1858488IUrea with inorganic phosphates (not ammonium) under pH control to avoid acidification; yield, gassing power, and keeping properties
Schneider and Dupont (1931); Dupont (1931); assigned to Intl. Wheat Malt Syrup Co.; December 1, 1927US (Chicago, Ill.)US 1829762; US 1829743PWheat malt extract or syrup
Claassen (1931, 1937); assigned to Pfeifer & Langen G. m. b. H.; March 27, 1928 (DE)DE (Dormagen)GB 346103 (DE 641742; DE 646579)PProtein-rich concentrate (peanut cake) is added to molasses and highly acidified (to solubilize proteins); gassing power and keeping properties
Dixon (1930); October 7, 1929 (GB)GB (Ipswich)GB 339047 (US 1914244)PAcid-treated malt (lactic or acetic acid); to improve nitrogen solubility; gassing power and keeping properties
King (1935); assigned to Natl. Grain Yeast Corp.; February 4, 1931US (Bloomfield, N.J.)US 2008584PWaste distillery slops (amino acids-rich) treated with lactic acid bacteria; with aqueous ammonia (to regulate acidity) in molasses-based media; sterile and clarified; yield
Braasch and Braasch (1937); October 13, 1931DE (Neumünster)DE 643339PAcid-treated peanut cake; cost
Wirtschaftliche Vereinigung der Deutschen Hefeindustrie (1936); April 26 and May 10, 1932DE (Berlin)DE 638575PHydrolyzed oilcake (peanuts, soya, and so on) mixed with molasses before its cleaning (to eliminate sulfuric acid)
Delta Technische Verkehrs-Aktiengesellschaft (1934); September 9, 1932 (DE)LI (Vaduz)FR 760306 (GB 424424; DE 637918; CH 171026)PPeptonized vegetable proteins (cereals or pulses such as soya); yield
von Gebsattel (1935); February 10, 1934 (DE)DE (Füstenberg)FR 786564 (GB 443269)PDebittered pulses (soya beans), not defatted; yield
Balla (1935); March 5, 1934 (HU)HU (Szántód)FR 786658 (GB 444929)AAcidified animal wastes (such as keratin, collagen, gelatin); cost and yield
Pollak (1937); February 21, 1935US (Woodmere, N.Y.); formerly AT (Vienna)US 2067002PProtein extracts from spent washes (distiller’, starch, and sugar byproducts)
Usines Le Lion d’Or and de Hemptinne (1946); September 18, 1946BE (St. Martins)BE 467984PCorn (cereals) steep waters
Fiechter (1969); assigned to Tettex A.G. (1968); November 12, 1965 (CH)CH (Zurich)GB 1116615 (FR 1522243; CH 473892)IAmino acids (glutamic acid, glutamine, aspartic acid or asparagine); yield (continuous process)
Mase and Fukatsu (1980); assigned to Sankyo Co., Ltd.; May 29, 1979JP (Tokyo)JP 55159792YYeast extract; gassing power
Izawa and others (2008); assigned to Fuji Oil Co., Limited; October 18, 2006JP (Osaka)WO 2008047596PProtein hydrolysate; freeze-tolerance

This section essentially deals only with organic nitrogen sources because little patenting interest appeared to have been given to the use of inorganic nitrogen (aqueous ammonia, ammonium sulfate, and others) for the production of baker's yeast. In this review, only 2 patents appeared to specifically mention such use: in 1883, Scard used miscellaneous ammonia salts (Gélinas 2010a) and, in 1895, Fritsche added ammonium sulfate to starch-based media (mentioned in the bottom note of Table 1).

Historical context

At the beginning of the 20th Century, saccharified cereals were the main growth media for baker's yeast manufacturing, and nitrogen was provided by ample addition of malt, in excess compared to that required for saccharification (Effront and Boidin 1916). Reason for overuse of malt was to supplement with easy-to-assimilate (peptonized) nitrogen. However, this solution was costly because it necessitated the addition of too much malt, as much as 10 times according to some inventors. During the preparation of cereal-based media, mash was submitted to a preliminary lactic souring with lactic acid bacteria, to free more nitrogenous foods (White 1954). This explains why inventors proposed new ways to solubilize nitrogen and get alternative nitrogen sources for baker's yeast growth media. Patenting activity on organic nitrogen stopped around 1939; interestingly, this coincided with the advent of lasting and widely accepted technological solutions for molasses clarification.

In later years, nitrogen sources in yeast technology would include aqueous ammonia and ammonium salts (Chen and Chiger 1985). However, the use of inorganic nitrogen salts for baker's yeast manufacturing was not readily accepted because it formed deleterious acids (sulfuric and others) that had to be neutralized with liquid ammonia. The finished product was very rich in protein, taking the character of starter yeast, being less durable and darker. The addition of inorganic nitrogen necessitated strict control of acidity but early controls of pH, acidity, and nitrogen in fermentation media were not very precise. This matter is outside the scope of this review and will be covered elsewhere.

Adjuncts and Growth Factors

Between 1900 and 2009, 28 patents were found on growth factors and minor ingredients for yeast manufacturing (Table 12). Miscellaneous ingredients were proposed to improve yeast yields (mainly), gassing power, and durability. Most of them were of inorganic or synthetic sources. In some patents, the use of plant hormones has also been mentioned. Some of the most innovative inventions included microbial co-cultures. Compared to nitrogen materials, there has been a lasting interest for optimizing baker's yeast activity with specific growth factors.

Table 12–.  Patents published between 1900 and 2009 on adjunct materials and growth factors for the manufacturing of fresh baker's yeast.
Inventor (publication y); priority dateCountry (city)Patent nr.OriginaDetails
  1. aB = bacteria; F = fermentation; I = inorganic or synthetic; O = others; P = plant; Y = yeast.

  2. bBreakthrough.

Effront (1903); August 30, 1902 (FR)BE (Brussels)GB 190219354 (FR 324124; DE 146499; AT 15834)PFatty acids, resinous acids, fatty soaps or resins (colophony or pine resin); with molasses- or grain-based media; yield
Pohl (1912); November 18, 1910DE (Rhondorf)DE 254707 (GB 191125570)IPotassium, calcium, sodium and aluminum silicates (called zeolites or geolites); for cereal-based media; yield
Hayduck (1923); assigned to Verein der Spiritus-Fabrikanten in Deutschland (1919); licensed to The Fleischmann Co. (US; CA); August 20, 1915 (DE)DE (Berlin)DE 303252 (GB 155291; US 1449104; CA 238177)ISodium salts (sodium sulfate, mono-basic and di-basic sodium phosphate, and sodium carbonate); to replace potassium salts (potassium sulfate and others); aerated; yield
Langemeyer (1924); Knappe (1924); November 23, 1922 (DE)DE (Mettingen)GB 207546
(FR 573544); CA 243096
FVolatile fermentation substances in exhaust air (nutrients such as lactates) are fixed by lime water and returned to the fermenting liquor; yield
Wroten (1926); assigned to Liberty Yeast Corp.; August 20, 1924US (Baltimore, Md.)US 1580550IDi-calcium phosphate (CaHPO4 2 H2O, called bone precipitate); alternative to ammonium phosphate or phosphoric acid; with cereal- or molasses-based media; cost and yield
Přibram and Wertheim (1928); April 29, 1925AT (Vienna)AT 111532P; ICarrot juice with metal salts, such as magnesium, iron, copper, zinc, aluminum, and chromium
Kottlors (1937); Stich and Kottlors (1943); April 14, 1932 and June 22, 1933 (DE)DE (Mannheim)US 2087059; DE 733598PHormones, such as auxine, the ovarian hormone in wheat germ; yield and gassing power
Vereinigte Mautner Markhof'sche Presshefe Fabriken and Szilvinyi (1935); October 20, 1933 (AT)AT (Vienna)FR 779794 (GB 445714; AT 146730; AT 148694; DE 658348)PPlant extracts (tomato juice or malt extract), rich in growth factors others than vitamins; yield
Pollak (1937); April 12, 1935bUS (Woodmere, N.Y.); formerly AT (Vienna)US 2094023 (GB 483774)PInositol (phytin) from spent waters of grain, starch, or alcohol factories; gassing power (high maltase) and keeping properties (low protease)
The Institutum Divi Thomae Foundation (1942); January 10, 1938 (US)US (Cincinnati, Ohio)FR 873553 (GB 550317)YYeast extract obtained by treatment with ultraviolet radiation; yield
Lange and Bohne (1943); assigned to I.G. Farbenindustrie AG; June 9, 1938bDE (Frankfurt)DE 731131INicotinic acid; gassing power
Schultz and others (1942, 1943a, 1943b, 1944); assigned to Standard Brands Inc. (1941); March 28, 1939, November 8, 1940, April 9, 1940, and June 13, 1940 (US)bUS (New York)GB 539825 (US 2322320); US 2285465; US 2333955; US 2333956; US 2354281IThiamine with factors inositol, alanine, leucine, and factor IIB present in tomato juice and the likes; vitamin B6 may also be added; yield
Eakin and Williams (1943); assigned to Standard Brands Inc. (1941); June 10, 1939 (US)bUS (Corvallis, Oreg.)GB 536510 (US 2322287)IVitamin B6; combined with inositol, aspartic acid, calcium pantothenate (or alanine), thiamine, and biotic acid, with thallium, zinc, manganese, boron, copper and iodine; yield
Schultz and others (1941); assigned to Standard Brands Inc. (1941); September 15, 1939 (US)bUS (New York)GB 532013 (US 2262735)IThiamine-rich yeast (vitamin B1) obtained by adding pyrimidine and thiazole in growth media; yield, gassing power, keeping properties, and color
Bergel and others (1945); assigned to Roche Products Limited and others (1943); September 17, 1941GB (Welwyn Garden City)GB 552713 (US 2372654)ICalcium pantothenate (manufacture); yield; brewing application is cited
Jørgensen (1954); assigned to Aktieselskabet Dansk Gaerings-Industri; April 23, 1951 (CH)DK (Copenhagen)FR 1051135 (CH 303261)IDiaminopelargonic acid or its derivatives; yield
Fischer (1954); assigned to Metal-Glass Products Co.; June 23, 1951US (Belding, Mich.)US 2689818YVitamins obtained by fermentation (yeast is propagated and later plasmolyzed); to prevent vitamin destruction during media sterilization
Looney (1954); assigned to The Distillers Co. Limited; July 18, 1951GB (Edinburgh)GB 709940BVitamins including biotin that may be synthesized by Pseudomonas fluorescens during yeast manufacture; yield
Just (1958); assigned to Versuchs- und Lehranstalt für Spiritusfabrikation; March 3, 1955DE (Berlin)DE 1039977IAneurin, biotin, niacin, and pyridoxine, 2 to 3 times more in beet molasses; to reduce (about half) seed yeast or fermentation time
Ushioda and others (1969); December 20, 1966JP (Tokyo)US 3476647IProduct of urea and acetaldehyde or crotonaldehyde (2-oxo-4-methyl-6-preido-hexahydropyrimidine; yield (seed yeast)
Evans (1991, 1992); assigned to Nutrition 21; July 29 1988 and October 9, 1990US (Puposky, Minn.)US 4997765; US 5085996IPicolinic acid and picolinate (chromium, zinc, iron, manganese); yield
Tuljakova and others (1997); January 30, 1997RURU 2099416IOrtho-phosphoric acid (sole source of phosphoric acid); yield
Kesojan and others (1999); assigned to Otkrytoe aktsionernoe obshchestvo “Reatehks”; November 20, 1998RU (Moscow)RU 2133271IMonopotassium phosphate (specific ratio to nitrogen); yield
Korjachkina and Bobrov (2004); assigned to Orlovskij gosudarstvennyj tekhnicheskij universitet; August 21, 2001RU (Orel)RU 2226832OExposition to light-emitting diode quantum radiation passed through walls of the equipment; yield
Tsujinama and Yamane (2006); assigned to Kanegafuchi Chemical Ind.; September 15, 2004JP (Osaka)JP 2006081446PLipid-protein complex; yield; no deteriorated flavor
Mingaleeva and others (2008); assigned to G Obrazovatel Noe Uchrezhdenie; December 1, 2006RURU 2326162ISodium salt of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid; yield and gassing power

Historical context

In the early days of industrial baker's yeast manufacturing, it was known that specific substances stimulated yeast reproduction. Originally known as “Bios,” these substances were considered essential nutrients. Molasses and cereal-based mashes were poor in Bios substances contrary, for example, to vegetable juices of all kinds and yeast autolysates. The dependence of the acceleration of multiplication on the Bios factors was not linear. In general, adjuncts and growth factors helped much to improve biomass yields or, to a lesser extent, gassing power.

For example, around 1940, the Standard Brands group was specifically interested to patent-protect the specific use of vitamin-enriched baker's yeast, as an indirect solution to enrich bakery foods; these commercial ingredients were developed through strains (Gélinas 2009) or fermentation conditions (Table 12). During 1941 and 1942, most of the bread manufactured in the United States was enriched with such patented thiamine-rich baker's yeast rather than with thiamin-enriched flour (Wilder and Williams 1944). When flour enrichment with both thiamine and riboflavin became mandatory in 1943, this led to a rapid abandon of vitamin-enriched baker's yeast because riboflavin-rich yeast was difficult to produce and had a color problem. Applications of scientific discoveries on vitamins to baker's yeast technology have been covered by White (1954).

Major Breakthroughs

Important breakthroughs from patents on yeast growth media had positive effects on yeast yield, color, gassing power, and keeping properties.

  • (A) Yield, color, odor, and keeping properties; molasses clarification. In 1931 and 1932, Ramesohl & Schmidt (Oelde, Westphalia, Germany) was the first to patent-protect the efficient use of centrifuges to clean molasses, thus avoiding a burden of work to the yeast manufacturers. Thorough elimination of coloring and dirty materials from molasses improved yeast appearance, odor, and, to some extent, yield and keeping properties.
  • (B) Yield, gassing power, and keeping properties; vitamins. Several key micronutrients used in the yeast industry were patent-protected. Media supplementation with inositol was first proposed in 1935 by Pollak from the United States (formerly from Vienna, Austria). In 1938, Lange and Bohne proposed the use of nicotinic acid in a patent assigned to I.G. Farbenindustrie AG (Frankfurt, Germany). In a series of patents filed in 1939, Standard Brands Inc. (New York, U.S.A.) applied scientific knowledge on the positive effect of several vitamins (including thiamine) on yeast yield, gassing power, and overall quality.

Technological Lessons from Patents on Growth Media

Patents are technological answers to timely problems. In retrospect, what technological lessons may be learned from these innovations?

  • 1Birth of the modern baker's yeast industry was around 1915 and probably earlier, depending on the country. Development of sourdough-type (artisanal) yeast substitutes was abandoned around 1900 to 1905 in Europe and 1915 to 1920 in North America, when pure and cheap forms of concentrated yeast for baking applications became available.
  • 2Molasses has been a key ingredient for yeast growth. Between 1920 and 1934, molasses replaced grain-based media and several processes were patented to clean it in the most efficient manner at the yeast manufacturing plant. However, alternative sugar sources to molasses are still needed and searched for.
  • 3Impact. With no less than 236 patents filed between 1900 and 2009, interest in growth media for baker's yeast was high, especially in the 1st half of the 20th century. However, only a few of these inventions appeared to have made a significant and lasting contribution to baker's yeast technology, except for molasses treatment and growth factors (vitamins).
  • 4Applicants. Germans and, to a lesser extent, Austrians were at the forefront of the patenting activity on baker's yeast media, as for the early days of yeast technology in the 19th century. Commercial interest was the greatest for molasses treatment and molasses alternatives. From the United States, The Fleischmann Co. (that became Standard Brands Inc. in 1929) was the single most active yeast manufacturer in patenting and licensing inventions developed in Europe.
  • 5Inventorship of patents is more difficult to determine than authorship of scientific publications. Names of individuals (true inventors) are not always mentioned in patents, so only the names of the applicants may be known. Contrary to scientific publications, this review has shown that the same invention may be claimed by several applicants who own the legal rights to a specific invention, and not only the one individual who developed an innovative idea. Many patents have been issued under different names, without cross-references to the priority file. When studying long-term technological trends, it is likely that licensing activity may be mixed up with true innovative activity. In the less recent literature, there is a true possibility to overestimate the number of patented inventions.

Impact on the Baking Industry

Since the 1920s, the massive use of molasses in fermentation media helped much to reduce the cost of commercial baker's yeast because molasses was much cheaper than cereals. Widespread acceptance of commercial baker's yeast by the baking industry would not have been possible without the introduction of such cheap molasses-based media.

Bakers now have access to a leaven material with specific color and odor associated with molasses remnants. This has been a major departure from yeast prepared from miscellaneous and poorly standardized grain-based ingredients. According to some inventors, yeast produced from cereal mashes had superior gassing power, keeping properties, and overall quality compared to early molasses-grown yeast products.

Between 1920 and 1940, the reduced cost and improved uniformity of molasses-grown yeast was a major determinant in the rapid expansion of industrial baking. Bakers had the possibility to expedite and better control the bread making process by increasing yeast concentration in dough. Hence, many customers from various parts of the world are now accustomed to the odor and taste of bread containing much yeast, departing much from typical sourdough-type taste.


Was the perfect growth medium for baker's yeast found and patent-protected? It seems not… Growth media alternatives to molasses are still being searched for among miscellaneous waste materials.

Acceptable baker's yeast was commercially available around 1915, probably earlier in some European countries, when yeast production switched from both artisanal plant-based dough and large-scale liquid media made with saccharified cereals. However, based on information disclosed in patents, the quest for acceptable yeast growth media mostly ended around 1939, about only 20 to 25 y after the onset of modern yeast technology.

Success of the baker's yeast industry has been much based on the low cost of molasses. By using cheap waste material from the sugar industry, yeast manufacturers avoided economic competition for human food, as was previously the case with cereal-based media. Such innovations would have limited impact on baker's yeast cost and quality without thorough control of fermentation conditions as will be shown in another publication.