Two techniques, ie, the climbing film, natural circulation evaporator and the double jacketed open pan evaporator, were used to concentrate the acidic whey. The unconcentrated (raw) whey, as well as the concentrated whey, were characterized physicochemically and incorporated into a French type (Hamam) bread dough formula as water replacers to provide 1% whey solids. The stability and the mechanical tolerance index of the French type bread dough were improved by the addition of whey solids, as were both the external and internal characteristics of the bread. The addition of whey solids also had a retardation effect on bread staling, and extended its storability by two days.