Effect of different stacking time on stacking fermentation of sauce-flavor Baijiu

Taking the second-round stacking fermentation of sauce-flavor (Jiangxiangxing) Baijiu as the research object, and the effect of different stacking time on the stacking fermentation of sauce-flavor Baijiu was explored by comparing the differences in the temperature of fermented grains, basic physicochemical indexes, microorganisms and flavor substances of base liquor at different stacking time. The results showed that the start time of the rapid warming phase of the outer Jiupei was delayed by 1d by extending the stacking time, and the top temperature of Jiupei increased from 44.2 ℃ to 47.9 ℃. Water content and acidity (41.87% and 1.04%) were slightly increased, while reducing sugar and starch contents (1.75% and 35.08%) were slightly decreased, with no significant differences (P>0.05). The number of total bacteria and total fungi and the viable rate of yeast (1.62×10⁷ CFU/g, 1.32×10⁷ CFU/g, 77.05%) increased significantly (P<0.05). Prolonging the stacking time could increase the total acid and total ester content of the base liquor to 2.89 g/L and 6.60 g/L, which was conducive to improving the quality of the second round base liquor. There were differences in the contents of 9 key flavor substances in the base liquor produced by different stacking time, among which the contents of acetaldehyde and acetal decreased, and the contents of ethyl valerate, n-propanol, isoamyl acetate, secondary butanol, furfural, methanol and propionic acid increased. Therefore, according to the actual production requirements, the reasonable control of stacking time was conducive to the quality control of stacking fermentation, and provided a new means for improving the production technology of sauce-flavor Baijiu.