Sourdough Temperature Guide
Fermentation speed is temperature-dependent. A 4-hour bulk at 76°F becomes 6 hours at 68°F — and 3 hours at 82°F. Multipliers below from Modernist Bread vol 3.
Timing calculator
- Multiplier at 76°F
- 1×
- Adjusted bulk ferment
- 4 h
- Adjusted final proof
- 12 h
How the math works
Multipliers are piecewise-linear interpolations between reference points measured by Myhrvold et al. in Modernist Bread vol 3. 76°F is the baseline (1.0×); every 10°F drop roughly doubles fermentation time, and every 10°F rise roughly halves it.
8 temperature ranges
You can only hit a number you can read
Every multiplier on this page assumes you know your actual kitchen and dough temperature — not a guess. An instant-read thermometer turns that from a guess into a number you control.
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Related references on this site
- Water temperature calculator — what temp water to land your dough at the target — the DDT math
- The full baking schedule & timeline — every stage from feed to bake, and how temperature moves each one
- All 25 recipes have a /timing page — every recipe shows bulk + proof at all 8 temperatures
- All 12 hydration levels — wetter doughs ferment slower; combine hydration + temperature
- Starter activity varies with temperature — warmer kitchen = faster peak; plan feed around bake schedule
- Whole-grains ferment faster — match temperature to flour absorption + enzymes
- Guide: temperature and time in sourdough — the piecewise-linear multipliers and how to use them
- Autolyse strategy by temperature — warmer kitchen needs shorter autolyse
- Levain build timing — time-to-peak in a hot vs cold kitchen