How to recycle yeast in your brewery?

In brew industry the water, hops, malt are the consumptions of disposables except for yeast, Not only will help save the cost also be beneficial for other business developments, Certainly that will be depend on is this kind of yeast will be deserve able to recycle….

The ideal recycle time is the 1 – 2 days after beer cold crash and what part of yeast we should recycle is the middle layer and means the amount we can acquire could up to 60-75%.

Top layer includes too much protein and impurities and the bottom layer includes too much dead cells.

We can confirm if the yeast could be still using for follow brews by following characteristics:

• Appearance: Looks purity with fresh surface & flavour, Firmly but not sticky

If the color is dark, it means that the wort filtration quality is poor, or the cold and hot coagulates are not discharged completely; the yeast mud is thin and thick, in general, the middle yeast mud discharged should be thick, if it is thin, it may be contaminated with bacteria.

• Smell and taste: It should have an inherent yeasty taste, without bitterness, sourness and other peculiar smells.

• Microscopic examination of yeast mud.

Microscopically examined yeast should be neat, plump and shiny, with thin cell walls, small vacuoles, inconspicuous contents, and no abnormal cells: Yeast cell activity is more than 95%~97% (0.1% methylene blue) The cells were stained in dark blue, and the cells were less than 3%~5%); the storage time in cold water (1~2℃) should not exceed 3 days.

A few points to note when recycling yeast:

• Yeast is very sensitive to the accumulation of CO2, so the yeast should be recovered in time;

• Usually fresh yeast can be used for 6 generations, and it is recommended to use no more than 4 generations for craft beer;

• Washing and sieving reduces yeast activity and also brings the risk of microbial infection. Yeast washing and sieving should be abandoned as much as possible;

• The fermentation performance of brewer’s yeast in the previous round of production was normal, such as hypoglycemia, diacetyl reduction, fermentation degree and brewer’s yeast sedimentation.

• Yeast should be re-added as quickly as possible. If the yeast is only stored for 2-3 hours, it is not necessary to cool it. During the shutdown period, yeast should also be stored at low temperature (0°C) in a certain concentration of beer or wort.

The usage rate of brewer’s yeast is generally not more than 5 generations, and craft beer is usually used for 4 times. Therefore, learning to recycle brewer’s yeast can reduce costs accordingly and improve your brewing level.

In addition, although the discarded yeast is no longer used in the brewing process of beer, it can be used in other aspects. The yeast cell contains almost no fat, starch and sugar, but contains excellent protein, complete B vitamins, a variety of Bio-minerals and high-quality dietary fiber. “Three low and four excellent” is a high-level summary of its nutritional characteristics: low-fat, low-sugar, low-calorie (no cholesterol), high-quality complete protein (containing 8 essential amino acids), complete B vitamins, 14 kinds of High-quality minerals and high-quality functional dietary fibers in the combined state of life. Various nutrients extracted from it are widely used in food processing, health care, biopharmaceutical industry and feed industry, and have broad prospects. The utilization and development of brewer’s yeast mud can not only reduce pollution and resource waste, but also generate additional economic benefits.