Fermentation timing

Pain au Levain — Timing by Kitchen Temperature

Baseline: 4.5h bulk + 12h proof at 76°F. Adjust for your kitchen below.

Temperature × time table

Kitchen tempMultiplierBulk (h)Proof (h)
62°F2.20×9.926.4
68°F1.58×7.118.9
72°F1.23×5.514.7
76°F1.00×4.512.0
80°F0.78×3.59.4
85°F0.56×2.56.7

Calculator pre-set to Pain au Levain

Multiplier at 76°F
1×
Adjusted bulk ferment
4.5 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.

Sources: Myhrvold et al., Modernist Bread vol 3 (temperature multipliers); Hamelman — Bread 3rd ed., Pain au Levain formula.