Temperature × recipe

Sourdough Brioche at 8895°F

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

Baseline bulk (76°F)
2h
Adjusted bulk
0.8h
Baseline proof
2h
Adjusted proof
0.8h
Multiplier
0.39×
Activity
extreme-mold-risk
Target hydration
55%
Bake temp
375°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 Brioche

Stand mixer mandatory. Combine flour, eggs, levain, salt, sugar in mixer. Knead 5 min on medium. Gradually add softened butter 1 tbsp at a time over 10 min. Knead until window-pane. 2h bulk at 76°F with 2 folds. Shape into log, loaf pan, or braided brioche mold. Cold retard overnight (12-16h at 38°F). Bake from cold at 375°F until internal 195°F (~35 min). Egg wash before bake for shine.

Calculator pre-set to these values

Multiplier at 92°F
0.39×
Adjusted bulk ferment
0.8 h
Adjusted final proof
0.8 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., Brioche formula adapted for sourdough.