Craft brewing equipment experts tell you some knowledge about yeast addition

Adding yeast is a step in the fermentation of beer, and the amount and timing of adding yeast are strict. Next, let me introduce some knowledge about yeast addition when brewing beer with small beer equipment.

Generally, the wort is pumped into the yeast multiplication tank, and the expanded yeast liquid or the recovered yeast mud is added. There are two methods for adding and multiplying the yeast.

1. Yeast addition method

(1) Add directly to proliferate. Stir the recovered yeast with the wort according to the required amount in the closed yeast adder. If the oxygen drop during fermentation is less than 6mg/L, it should be ventilated for several minutes, and the shift should be increased by 4~5 within 18~24h. This method is adopted by most breweries in my country.

(2) Additional method or division method multiplication method. This method is similar to expanding culture, gradually increasing the number of yeast in the fermentation broth, and properly ventilating after each addition. The specific methods are various. For example, add the yeast mud required by a yeast multiplication pool into the pool, within 12 hours of yeast multiplication, add the whole amount of wort in 3~4 times; when the amount of yeast mud is insufficient, add wort to the multiplication pool. 2~24h, and then divided into two pools, each filled with wort, and continued to proliferate for 12h. After the yeast multiplies in the multiplication tank, the number of yeast reaches 7X16/mL, and the germination rate is about 7. There are white creamy foams rising around the multiplication tank and moving to the middle. At this time, the yeast liquid can be pumped into the main fermentation tank.

2. The amount of yeast added

The amount of addition is usually calculated according to the percentage of muddy yeast to wort volume, generally 0.5~0.65, and the concentration after inoculation is usually 80,000~120,000/mL. Temperature, wort concentration and addition method are properly adjusted. If the wort concentration is high, the number of generations of yeast used is large, and the inoculation temperature and yeast concentration are low, the inoculation amount should be slightly larger, and vice versa.