To size a yeast propagation vessel, brewers first determine the yeast pitching rate required for their specific beer style. Once this ratio is determined, the brewer can calculate the total number of yeast cells required for a given batch size and wort gravity. Proper container size ensures optimal yeast health, growth and fermentation performance. The volume of yeast removed from the propagator or slurry usually depends on the concentration of viable yeast cells in the suspension. The brewer’s goal is to have a specific number of yeast cells per milliliter of wort, and the volume of yeast slurry required to achieve this is affected by the density of the yeast cells in the slurry.

• For Ales: Common pitching rates for ales are around 750,000 to 1 million cells per milliliter per Plato. If the yeast slurry has a concentration of about 1 billion cells per milliliter, you will need: 1 to 2 liters of yeast slurry per barrel (bbl) of wort.
• For Lagers: Lagers generally must higher pitch rates, around 1.5 to 2 million cells per milliliter per Plato. Again using the example of a yeast slurry concentration of 1 billion cells per milliliter, what is required is: 2 to 4 liters of yeast slurry per barrel (bbl) of wort.

Most professional craft brewers perform cell counts to determine the exact concentration of their yeast slurry, allowing them to set the optimal volume for each batch of beer. The amount of yeast a brewery requires is affected by the diversity of yeast strains maintained and the frequency of brewing and production. At Micet, our experienced sales team can guide you in determining the appropriate size and number of containers that will best suit your yeast handling needs. While we offer standard container sizes of 3, 5, 7, 10 and 15 barrels, we also specialize in custom designs and sizes.