Brewing Process Control and its knowledge

Brewing Process Control

1. Fermentation temperature

Both the non-enzymatic decomposition of α-acetolactate and the enzymatic reduction of diacetyl are temperature-dependent. The higher the temperature, the faster the reaction. Therefore, if the main fermentation temperature is increased, or the fermentation temperature is maintained at a higher temperature before the end of the main fermentation, the diacetyl is reduced quickly, and the post-fermentation time of the beer is greatly shortened.

2. Add high sparkling wine

When the diacetyl content of the fermented beer cannot be reduced normally, try adding 20~30% high-bubble wine, and use the yeast of the high-bubble wine to reduce the diacetyl.

3. CO2 washing

Scrubbing with high-purity CO2 gas produced by fermentation removes volatile diacetyl. Although CO2 washing can reduce the diacetyl content, it resuspends the gradually deposited yeast, condensate, etc., which may affect the filtration of beer.

5. Beer packaging

On the one hand, it is necessary to reduce the oxygen content, and on the other hand, it is necessary to control the temperature and time of pasteurization, because with the increase of pasteurization temperature, it is easier to decompose acetolactate into diacetyl under aerobic and higher temperature conditions. . Practice has proved that instantaneous sterilization produces less diacetyl than long-term low-temperature sterilization.

4. Beer storage and filtration

Inhalation of oxygen during wine storage and filtration accelerates the decomposition of α-acetolactate into diacetyl. Therefore, when beer is filtered, efforts are made to reduce the inhalation of oxygen, and the content of diacetyl can be controlled under certain conditions. The general process is as follows:

4.1 Convert diacetyl to hydroxybutanone and butanediol.

4.2 Diacetyl reacts with sulfite to form a non-volatile complex to remove the odor caused by diacetyl.

4.3 Reduces diacetyl content by preventing the conversion of acetolactate to diacetyl.

6. Prevent bacterial contamination

Large amounts of diacetyl and acetolactate are produced if the wort or additive yeast is infected with lactic acid bacteria or tetrad. Wort or yeast added to infect other miscellaneous bacteria. Although these bacteria do not produce diacetyl by themselves, they can seriously affect the activity, state and other metabolism of yeast, and may also increase the content of diacetyl. Therefore, it is necessary to control the hygiene of the brewing process. And environmental sanitation, avoid wort or add yeast process contamination.