The invention discloses a high-concentration
alcohol fermentation method, which comprises the following: a step of distiller's
yeast cultivation, in which yeasts are cultured at 31 DEG C and the concentration of distiller's
yeast fermented liquor is 2 to 3 percent lower than that of saccharified fermented liquor in
fermentation; a step of
fermentation, in which an early fermentation stage is mainly to culture fermentation capacity (to enrich
zymase of yeasts), the fermentation temperature is kept between 34 and 35 DEG C till the concentration of the
alcohol is 8 percent, then the temperature is reduced to 33 DEG C till the end of the fermentation, at least 200ppm of
free amino nitrogen is kept in a fermentation tank, the
metabolism of the yeasts is promoted, and the number of the yeasts in the fermentation tank is ensured; and a step of adding saccharifying
enzyme, in which 2 / 3 of saccharifying
enzyme is added into a saccharification tank first, the rest saccharifying
enzyme is added 8 to 10 hours later, and thus, the post saccharification can be performed at a higher speed in the later stage of fermentation in the presence of the saccharifying enzyme and the fermentation speed is ensured. In the invention, two problems of fermentation concentration and fermentation period, which influence fermentation concentration, are solved, the high-concentration
alcohol fermentation can be realized, the fermentation effect of the alcohol is desirable, and the fermentation period is short.