What is the sequence for expanding the culture of brewer's yeast? What are the technical requirements for expanded cultivation of brewer’s yeast? What are the basic requirements for yeast expansion equipment?

Sequence for expanding brewer’s yeast culture

Inclined test tube (original strain)→Fuchs flask or test tube culture→Pasteur flask or Erlenmeyer flask culture→Caffeine jar culture→Hansen jar culture→Yeast expansion culture tank→Yeast propagation tank→Fermentation tank.


Technical requirements for expanded culture of beer yeast


1. All culture equipment must be thoroughly cleaned, plugged with cotton plugs, and sterilized by dry heat at a sterilization temperature of about 170°C;

2. The culture medium for culture should be wort with hops added on site. It should be heated and boiled and clarified by adding protein. After intermittent sterilization with steam, it should be stored in an incubator at 25°C for 2 to 3 days. It can only be used after it is proven that there is no contamination. ;

3 The dilution factor for each expansion is about 10 times or less;

4. After each transplantation and inoculation, the development of yeast cells must be examined under a microscope;

5. With the expansion of culture at each stage, the culture temperature gradually decreases to adapt to on-site fermentation conditions;

6. At each expanded culture stage, parallel culture should be carried out: 4 to 5 test tubes, 2 to 3 Pasteur flasks, and 2 Catcher jars. The best ones should be selected for expanded culture.

 

Basic requirements for yeast expansion equipment

 

1. Achieve sufficient ventilation and oxygen saturation. As for the use of continuous or intermittent methods, it depends on the corresponding ventilation cycle;

2. Mix and distribute evenly in the expansion tank to ensure vigorous contact between yeast cells, wort and bubbles;

3. Proper temperature control during the expansion stage and when cooling to the inoculation temperature at the end of expansion;

4. Expand culture under good microbial conditions;

5. Appropriate measurement and adjustment technology to ensure the stability of the process.