Sourdough Levain Build Calculator
Build the exact levain a recipe calls for from a starter:flour:water ratio — how much ripe starter, flour and water to mix, plus the levain hydration.
How it works
Each part = levain needed × (its parts) ÷ (starter + flour + water parts) · Levain hydration % = water ÷ flour × 100
A levain (or "offshoot") is a fresh preferment built from a small amount of your mature starter plus flour and water, made the night before you bake. A ratio like 1:4:4 means one part starter, four parts flour, four parts water — a low inoculation that ferments slowly and predictably. Equal flour and water parts give a 100%-hydration liquid levain; using less water builds a stiffer levain that ferments more slowly and tastes milder.
Worked example
To build 200 g of levain at 1:4:4, the parts total 9. Starter = 200 × 1⁄9 ≈ 22 g, flour = 200 × 4⁄9 ≈ 89 g, water = 200 × 4⁄9 ≈ 89 g. Because flour and water are equal, the levain is 100% hydration.
Frequently asked questions
How much starter should I use in a build?
A small inoculation (5–20% of the flour) ferments over 8–12 hours and suits an overnight build; a larger one (30–50%) ripens in 3–5 hours. The 1:4:4 default is about a 20% inoculation.
How do I know the levain is ready?
It should roughly double, dome on top and pass the float test — a spoonful dropped in water floats when it is fully aerated and at peak activity.
What is the difference between a starter and a levain?
The starter is the culture you keep and feed indefinitely; the levain is a one-time build made from it in the exact quantity and hydration a specific recipe needs, so you never deplete the mother starter.
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This calculator is for educational purposes. Double-check important results before acting on them.