Chapter 4

Brewers Yeast

Yeast Storage

In most breweries, yeast is stored during the period between cropping and re-pitching. Pitching yeast may be stored within the brewery as slurry in a yeast collection vessel, or as slurry stored under a layer of water or beer, or as pressed cake.

Yeast Collection Vessels

Most modern breweries store their yeast in sophisticated collection vessels under filtered sterile air or inert sterile gas pressure with external cooling and equipped with low shear stirring devices.

Slurried Storage Systems

Slurried storage systems are usually self-contained, thereby reducing the risks of contamination. Slurry yeast has the advantage over pressed yeast in that it gives more vigorous fermentations, requires lower pitching rates, and can be stored for longer periods (usually fewer than 4 weeks) without affecting viability.

Pressed Cake

Alternatively, yeast can be stored as pressed cake. The yeast recovered is stored at 0C before re-suspension in wort for pitching (42).

Click on the following topics for more information on brewer's yeast.