Yeast Pitch Rate and Cell Count
Computes cells required from the pitch rate, volume, and degrees Plato, then the slurry volume at a given viability.
Example
You enter
- Batch volume (gal) 310
- Original gravity 1.055
- Pitch rate (million/mL/deg P) 0.75
- Slurry concentration (cells/mL) 1200000000
- Viability (%) 90
- Viability after ageing (%) 60
- Stronger beer to compare 1.08
You get
- Degrees Plato 13.50 deg P
- Cells required 11883500000000
- Slurry ml 11003.3
- Slurry to pitch 2.91 gal (11.0 L)
- At the aged viability 4.36 gal -- 50% more for the same pitch
- Strong plato 19.1852
- Strong cells required 16885000000000
Checked against published worked examples from: Colorado Brewers Guild.
Details, formula, and sources
ScopeThe worked 310 gal ale at 1.055 needs 11.9 trillion cells, or 2.9 gal of slurry at 90% viability. At 60% viability it is 4.4 gal, and pitching the old volume by the mark underpitches by a third.
Formula or tablecells = rate (million/mL/degP) x volume mL x degP, with degP = 259 - 259/SG; slurry = cells / (concentration x viability).
Source and editionCustomary pitch rates of 0.75 for ales and 1.5 for lagers. A viability count on the day of pitching governs.
Free accessPublic arithmetic.
What governsEstimate. AHJ and licensed professional govern.
API field namesbatch_volume_gal, original_gravity, pitch_rate_million_per_ml_plato, slurry_cells_per_ml, viability_pct, aged_viability_pct, strong_original_gravity, plato, cells_required, slurry_ml, slurry_gal, aged_slurry_gal, strong_plato, strong_cells_required
- Plato the 259 - 259/SG approximationbrewing practice