Sourdough bread calculator
Sourdough loaves with the starter amount computed from your fermentation time, temperature and starter condition.
Yeast is calculated assuming a 6 °C fridge.
The starter amount is computed from your fermentation time, temperature and starter condition.
1 × 900 g · 75% hydration
Type how much flour you have — the portion weight recalculates.
Wheat sourdough bread with no commercial yeast at all. What makes this calculator different: the starter amount is not fixed — it is computed from your time, temperature and the condition of your starter, the way an experienced baker judges it.
How it works
Starter computed from the plan
Tell it how many hours the dough will ferment and at what temperature, and the calculator sets the starter percentage: a short, warm plan needs more of it, a long, cool one less. The model assumes fermentation speed doubling every ~7 °C, with the fridge at 6 °C.
Starter condition
The same starter can be vigorous (fed regularly, doubling within hours) or weak (straight from the fridge, long unfed). Pick the condition and the dose adjusts — a weak starter gets a larger share.
Hydration and salt
The default 75% water and 2% salt is a proven starting point for a dutch-oven or stone bake. Note the water inside the starter itself is not decomposed yet — treat hydration as an approximation (exact starter decomposition arrives in a future version of the calculator).
FAQ
How much starter for a loaf?
It depends on the plan: around 8 warm hours lands in the high-teens to twenties as a percentage of flour, a long cold ferment far less. That is why the calculator asks for time and temperature instead of quoting one number.
My starter sat in the fridge for weeks — what do I pick?
Pick “weak”, and ideally refresh it with 1–2 feedings before baking. After two days of regular warm feedings, go back to “normal”.
Can part of the fermentation happen in the fridge?
Yes — the classic move is proofing the shaped loaf overnight in the fridge. Enter the total time and the cold share; at 6 °C fermentation nearly stops, which the model accounts for.