Yeast calculator
How much yeast does your beer need? The calculator tells you how many packs of dry yeast to use, or how big your starter has to be.
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Full calculator in the appIt picks up your values, plus measurements, corrections and every recipe to load.
Why the amount of yeast matters
Too little yeast starts slowly, produces more off-flavours such as esters, fusel alcohols or diacetyl, and often leaves the beer too sweet. Too much yeast is less of a problem but can mute the character of a yeast.
Brewers use the pitch rate: about 0.75 million cells per millilitre of wort and degree Plato for ales, around 1 million for strong ales and around 1.5 million for lager, because yeast works more slowly at cool temperatures.
Dry yeast and liquid yeast
An 11.5 g (0.41 oz) pack of dry yeast holds many billions of live cells and keeps for a long time. The calculator shows how many packs you need and compares this with the manufacturer’s guide.
Liquid yeast loses about a fifth of its live cells every month. The calculator estimates from the production date how many cells are still alive and works out how big a starter has to be – on a stir plate or just shaken.
Good to know
All values are guide values. The starter calculation follows a well-known growth model for homebrewers. The calculator remembers your inputs and uses batch size and gravity from the final beer calculator.