This tool estimates number of yeast cells necessary for healthy fermentation of specified beer. The tool also estimates appropriate yeast amount based on yeast type and age.
Formulas and assumptions are based on article published on grádyš website (in Czech only).

Notes:

• Tool is available only for registered users.
• Choose units.
• Enter Batch Size (wort volume in fermenter) and Original Gravity.
• Enter Coefficient according to following instructions:
  • 0.75 - ALE (up to 15°Plato)
  • 1.0 - strong ALE (more than 15°Plato)
  • 1.5 - lager
  • 2.0 - strong lager
• Choose yeast type - dry, liquid or slurry - and enter manufactured date.
• Click on Calculate button to see yeast cell count estimation.
• When Yeast Date is provided this tool also estimates yeast viability and yeast amount (i.e. weight of dry yeast, number of packs/vials of liquid yeast, slurry volume).
• All calculations are based on following assumptions:
  • There are 20 billions of yeast cells in 1 gram of new dry yeast with 90% viability. Viability drops 0.3% per month.
  • One pack (Wyeast) or vial (WhiteLabs) of liquid yeast contains 100 billions of cells. Viability drops 20% per month.
  • One milliliter of yeast slurry contains 1-3 billions of cells. Viability drops 50% per month.