Fermentation timing

40% Rye Hearth Loaf — Timing by Kitchen Temperature

Baseline: 3.5h bulk + 8h proof at 76°F. Adjust for your kitchen below.

Temperature × time table

Kitchen tempMultiplierBulk (h)Proof (h)
62°F2.20×7.717.6
68°F1.58×5.512.6
72°F1.23×4.39.8
76°F1.00×3.58.0
80°F0.78×2.76.2
85°F0.56×2.04.5

Calculator pre-set to 40% Rye Hearth Loaf

Multiplier at 76°F
Adjusted bulk ferment
3.5 h
Adjusted final proof
8 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., 40% Rye formula.