1.The time of yeast recovery
A. Middle of primary fermentation, 10 or 12℃; B. Diacetyl reduction finished; C. Diacetyl reduction finished; D. Diacetyl fermentation finished.
B. Diacetyl reduction complete.
C. Cooling to 5°C;.
D.Cooling to 0-1°C.
Yeast should not be recovered after 7 days, because too long storage in the beer will affect the yeast activity.
The yeast will be at its best when the residual sugar drops to 3.6-3.8°P or before the second cooling. Recovered yeast should be clean, pure, free of bad bacteria, neatly arranged cells, and methylene blue staining should be less than 5%.