Levain Builder: Target Amount & Reserve

Work backward from the levain your recipe needs. Include a reserve and calculate seed starter, fresh flour and water at your chosen hydration.

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Levain Builder: Target Amount & Reserve
At 100% seed and target hydration, 3 gives a 1:3:3 seed:flour:water feed. Water is recalculated when either hydration changes.

Total levain

Seed starter
24.3 g
Fresh flour
72.9 g
Fresh water
72.9 g
Total levain
170.0 g
Levain needed for the recipe
150.0 g
Reserve for your next feed
20.0 g

Seed : flour : water: 1 : 3 : 3

Weights are displayed to 0.1 g. Small differences in their rounded sum are normal. Hydration is a formula ratio, not a promise about dough handling or fermentation time.

Use this levain in the recipe converter →

Read the worked example →

Method and limits

Separate the recipe amount from the reserve

If the dough needs 150 g levain and you want 20 g left for a future feed, build 170 g. The reserve stays outside the dough formula. Putting all 170 g into a recipe written for 150 g changes both its flour and water totals.

The reserve field is an amount you choose, not a recommended minimum. You can set it to zero if you keep a separate mother starter. Allow for any expected jar or spoon losses by increasing your chosen reserve; the calculator does not add a hidden allowance.

Different seed hydration changes the water addition

The builder’s ratio field specifies fresh flour per gram of seed. It calculates fresh water to achieve the final hydration, counting water already in the seed. This makes the same field useful with a stiff or liquid starter.