The time and principle of recycling yeast

helen 2017-05-03

The time and principle of recycling yeast

1.Time of recycling yeast
A.At the middle of primary fermentation, 10 or 12℃;
B.Diacetyl reduction is finished;
C.Cooled to 5℃;
D.Cooled to 0-1℃.
The yeast after seven days should not be recycled as it’s liveness is affected due to long time storing in beer.

2. Principle of recycling yeast
After sedimenting in the fermenter bottom, the yeast usually is under 0.19-0.24Mpa pressure. Therefore, the yeast must be recycled with pressure. If drained with atmospheric pressure, the yeast would be hurt even broken because the pressure is decreased suddenly. In this case, the death rate of yeast would rise no doubt. In addition, the CO2 would also blow off to produce amount of foam, which will make the white yeast become brown. 

The yeast vitality will be best when residul sugar is decreased to 3.6-3.8°P or before the second cooling. The recycled yeast should be clean, pure, no bad bacterial, cells in order and methylene blue staining should be lower than 5%.

Edited by Vicky

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