The main fermentation of the wort is carried out in the fermentation tank. The yeast multiplies and grows and "eats" the carbohydrates of the wort, producing alcohol, carbon dioxide and flavor substances. The duration of the main fermentation is 5-10 days to obtain a beer slurry. During the fermentation process, the concentration of wort is measured. When the required concentration is reached, the beer is cooled to a temperature of 0.5-1°C, and then the fermentation is continued in the tank, or the beer is pumped to another fermentation tank for fermentation.