Starter Size For Yeast Calculator

Work out starter size for yeast instantly with clear inputs, formula shown and shareable results.

About Starter Size For Yeast Calculator

A yeast starter grows the cell count to the pitching target. A litre of 1.037 starter wort on a stir plate supports roughly 14 billion new cells; intermittent shaking supports around 7 billion and a still starter about 4 billion. Starter wort is made at about 100 grams of dried malt extract per litre.

Formulas

Starter volume

Volume = cells to grow / growth capacity per litre

Starter wort

Dried malt extract approximately 100 g per litre gives 1.037 gravity

Worked example

With the default values below, Starter Size For Yeast Calculator returns Starter Volume Required of 10.714. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cells Requiredminimum 0 billion: 250 billion
Cells Availableminimum 0 billion: 100 billion
Starter Gravityaccepts 1.005–1.1: 1.037
Starter Aerationone of No agitation, Intermittent shaking, Stir plate: Stir plate

Results

Starter Volume Required: 10.714
Cells To Grow: 150.00
Dried Malt Extract Required: 1,026.75
Growth Capacity Per Litre: 14.000

Step by step

1Values used
2Starter volume
3Starter wort
4Starter Volume Required= 10.714
5Cells To Grow= 150.00
6Dried Malt Extract Required= 1,026.75
7Growth Capacity Per Litre= 14.000

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does a stir plate help so much?

Continuous agitation keeps cells suspended and maintains dissolved oxygen and carbon dioxide removal, both of which raise the cell yield per gram of extract substantially.

Should the starter be pitched whole or decanted?

Decant the spent starter wort if it is more than about 5% of the batch volume, since its oxidised character and different profile can affect the beer. Cold crash first to settle the yeast.