Temperature × recipe

40% Rye Hearth Loaf at 6872°F

Adjusted timing: 4.7h bulk + 10.8h proof (multiplier 1.35×).

Baseline bulk (76°F)
3.5h
Adjusted bulk
4.7h
Baseline proof
8h
Adjusted proof
10.8h
Multiplier
1.35×
Activity
moderate
Target hydration
78%
Bake temp
475°F

Why the timing shifts

Most home kitchens — typical year-round room temperature. Ferment slightly longer than 76°F baseline. Recipe times generally work as written with minor extensions (+20%). Good balance of schedule manageability and flavor development. Most Hamelman and Tartine formulas are written assuming this range.

Technique for 40% Rye Hearth Loaf

Autolyse wheat flours 30 min with water. Add rye flour, levain, salt. Mix thoroughly by hand (rye prevents useful kneading). 3-4 coil folds over 3h bulk at 76°F. Shape in floured banneton. Cold retard 8h. Bake in preheated dutch oven at 475°F: 20 min lid on, 20 min lid off.

Calculator pre-set to these values

Multiplier at 70°F
1.35×
Adjusted bulk ferment
4.7 h
Adjusted final proof
10.8 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, Modernist Bread vol 3 (temperature multipliers); Hamelman — Bread 3rd ed., 40% Rye formula.