Yeast Pitch Rate Calculator

How it works

Cells (billion) = pitch rate (million/mL/°P) × volume (mL) × °Plato ÷ 1000; liquid viability ≈ 100% − 21.5% per month; dry sachet ≈ 200 billion

Yeast health at pitching decides how a fermentation starts and how it tastes. The standard targets — three quarters of a million cells per millilitre per degree Plato for ales, twice that for lagers — come from professional practice and scale with both volume and gravity, so a 20 litre 1.056 ale wants roughly 200 billion cells while the same volume of 1.080 lager wants over 550 billion. A fresh liquid pack holds about 100 billion and loses roughly a fifth of its viability each month in the fridge, which is why most all-grain ale batches benefit from a starter and lagers almost always need one. Dry yeast is easier: an 11 g sachet carries around 200 billion cells and keeps well, so two sachets cover most lagers.

Worked example

20 L of 1.056 (13.8 °P) ale at 0.75 M/mL/°P: 207 billion cells. A two-month-old liquid pack has about 57 billion viable, so make a starter or pitch four packs; one dry sachet (≈ 190 billion) is close enough.

Frequently asked questions