Temperature × recipe

Hokkaido Milk Bread (Sourdough) at 6872°F

Adjusted timing: 3.4h bulk + 4.1h proof (multiplier 1.35×).

Baseline bulk (76°F)
2.5h
Adjusted bulk
3.4h
Baseline proof
3h
Adjusted proof
4.1h
Multiplier
1.35×
Activity
moderate
Target hydration
72%
Bake temp
350°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 Hokkaido Milk Bread (Sourdough)

Make tangzhong: 25g bread flour + 125g water, heat in pan stirring to 65°C until thick paste. Cool. Combine tangzhong with other dough ingredients + levain. Knead 10 min. 2.5h bulk. Divide into 3 pieces, roll each into rectangle, fold thirds, roll into coil. Place coils side-by-side in oiled loaf pan. Proof 3h until risen 1 inch above pan. Bake 350°F for 30-35 min until golden and internal 190°F.

Calculator pre-set to these values

Multiplier at 70°F
1.35×
Adjusted bulk ferment
3.4 h
Adjusted final proof
4.1 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); Asian bakery tradition; adapted for sourdough per King Arthur.