Temperature × recipe

Sourdough Challah at 8895°F

Adjusted timing: 0.8h bulk + 1.2h proof (multiplier 0.39×).

Baseline bulk (76°F)
2h
Adjusted bulk
0.8h
Baseline proof
3h
Adjusted proof
1.2h
Multiplier
0.39×
Activity
extreme-mold-risk
Target hydration
55%
Bake temp
350°F

Why the timing shifts

Very hot — avoid. Mold risk rises sharply above 85°F. Fermentation outpaces structural development. Levain becomes unbalanced toward lactic acid producers, creating cloying sour flavor. Only use briefly for refreshing starters or if absolutely unavoidable. Move dough to cooler location, or skip this bake and wait for cooler conditions. If baking must happen, reduce levain to 8%, bulk 90 min max, get into refrigerator immediately after shaping.

Technique for Sourdough Challah

Stand mixer: combine flour, eggs, water, oil, sugar, levain, salt. Knead 8 min on medium. 2h bulk at 76°F with 2 folds. Divide into strands (3/4/6), braid. Proof 3h at 76°F. Egg wash, optionally top with sesame or poppy. Bake 350°F for 30 min until internal 190°F.

Calculator pre-set to these values

Multiplier at 92°F
0.39×
Adjusted bulk ferment
0.8 h
Adjusted final proof
1.2 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); King Arthur Baking — Sourdough Challah + Jewish tradition.