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Sourdough starter feeding calculator
Build the levain your dough needs and keep some starter for the next bake. Ratios below mean starter : fresh flour : fresh water, by weight.
40 g starter + 80 g flour + 80 g water
200 g total: use 180 g in dough and keep 20 g. Final hydration is 100%.
Watch the starter’s rise and peak; this ratio does not establish a ready time.
Starter and levain: what are you building?
The starter here is the ripe starter you take from your jar to feed (some bakers call it the seed). Levain is the portion built for your dough. What you keep is the amount left after taking that levain, not extra flour hidden in the formula. This tool scales an established starter; it is not a timetable for making one from scratch.
Timing depends on temperature and the culture
Brod & Taylor publishes these starting points for a 1:4:4 feed of an established starter kept at a set temperature. They are feeding intervals, not a promise that levain will be ripe at that hour. Flour and culture can change the timing. There is no interpolated estimate for other temperatures or ratios.
| Temperature | Feed interval |
|---|---|
| 7°C / 45°F | 120 hours |
| 10°C / 50°F | 72 hours |
| 12°C / 54°F | 48 hours |
| 20°C / 68°F | 24 hours |
Mark the starting level on the jar and look for a repeatable rise and peak. Times for a cool starter won’t hold on a warm counter. Choose a jar and a warm spot only if your current equipment cannot do the job.
How the feed is calculated
Starter = total needed ÷ (1 + flour ratio + water ratio). Fresh flour and fresh water are their ratios multiplied by the starter weight. Total hydration includes the flour and water already in the starter; inoculation here means starter weight divided by fresh flour weight.
Use the levain’s flour and water in the batch calculator, then plan the bake backwards. For a starter that does not rise or looks or smells wrong, check what is wrong with it.