Studies on the brewing of alcoholic beverage by the system of fermentation following after saccharification. Part 3. Studies on conditions of fermentation following after saccharification. 2.

Effects of fermentation conditions on yeast growth and the components in fermented liquor were investigated.(1) In fermentation of synthetic medium with stirring, when the head space of fermentor wa filled with nitrogen gas, dissolved oxygen reduced, and the growth rate and the production rate of alcohol were lower comparing with those in fermentation without nitrogen gas.(2) The time, at when the head space of fermentor was filled by the nitrogen gas, was delayed, in this case the final yeast cell number and the fermentation rate increased. So existence of oxygen at an early fermentation stage was effective on yeast growth.(3) In fermentation with stirring, the growth rate of yeast was higher than that in fermentation without stirring.(4) Acocording to increase of final yeast cell number, concentration of amino acids became low and concentration of amyl alcohols and isoamyl acetate became high in fermented medium.(5) In fermentation of saccharified solution with stirring, final yeast cell number and concentration of higher alcohol and isoamyl acetate were higher and concentration of amino acid was lower than that in fermentation without stirring. The taste and flavor of fermented liquor with stirring was better than that without stirring.The changes of the concentration of various components such as organic acids, amino acids, diacetyl and acetaldehyde, during fermentation with stirring were different from those in without stirring.