The Oven SpringSourdough starter feeding calculator
Build the levain your dough needs and keep some starter for the next bake. Ratios below mean seed starter : fresh flour : fresh water, by weight.
40 g seed + 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 seed is established starter used to inoculate fresh flour and water. Levain is the portion built for your dough. Reserve is the amount left after taking that levain, not extra flour hidden in the formula. This tool scales an established culture; it is not a timetable for creating a starter from scratch.
Timing depends on temperature and the culture
Brød & Taylor publishes these starting points for a 1:4:4 maintenance feed at a controlled 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. Do not apply cool-storage intervals to a warm counter. Choose a jar and temperature-control setup only if your current equipment cannot do the job.
How the feed is calculated
Seed = total needed ÷ (1 + flour ratio + water ratio). Fresh flour and fresh water are their ratios multiplied by seed weight. Total hydration includes the flour and water already in the seed; inoculation here means seed 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 has an unusual appearance, check starter troubleshooting.