Brewery Setup Blog

How to recycle yeast from a brewery?

In the brewing industry, water, hops, and malt are disposable consumables other than yeast, which not only saves prices, but also benefits the growth of various other businesses. Of course, it depends on whether the yeast has a certain recycling value.

The best recovery time is 1-2 days after the beer is cooled, the yeast component we need to recover is the center layer, which means that the amount we can get can be as high as 60-75%. The leading layer is composed of excess healthy proteins and impurities, and the lower layer is composed of excess dead cells.

We can verify that the yeast can still be used for subsequent brewing by the following properties：

Appearance: It looks pure, with a fresh surface, and the taste is firm and not sticky. If the color is darker, it means that the wort filter quality is poor, or the hot condensation block is not completely released; the yeast mud is thin and viscous, and the released central yeast mud must be viscous. If it is thin, it may cause bacterial contamination.

Smell and Taste: There should be a solid yeasty smell, no bitterness, sourness and all sorts of other odd off-tastes. Microscopically analyzed yeast should be intact, shiny, and plump, with a slender cell wall surface, tiny vacuoles, inconspicuous material, and no unusual cells: yeast cells task greater than 95% to 97% (0.1% sub- A blue). The cell discoloration is dark blue, and the cells are much lower than 3%~5%); the storage time in cold water (1~2℃) shall not exceed 3 days.

There are a few considerations to keep in mind when recycling yeast:

Yeast is very sensitive to the accumulation of CO2, so it is necessary to recycle the yeast in time; fresh yeast can generally be used for 6 generations, and craft beer is recommended to use no more than 4 generations; sieving and cleaning reduce the activity of yeast, and also bring microorganisms. risk of infection. Yeast sieving and cleaning must be as high as possible; fermentation efficiencies of brewer's yeast are typical, such as low blood sugar, reduced diacetyl, fermentation levels, and brewer's yeast settling.

Yeast is re-added as soon as possible. If the yeast is only kept for 2-3 hours, cooling is not required. During downtime, yeast needs to be kept at a reduced temperature (0°C) in a specific concentration of beer or wort.