Temperature × recipe

Spelt Hearth Loaf at 8895°F

Adjusted timing: 1.2h bulk + 2.4h proof (multiplier 0.39×).

Baseline bulk (76°F)
3h
Adjusted bulk
1.2h
Baseline proof
6h
Adjusted proof
2.4h
Multiplier
0.39×
Activity
extreme-mold-risk
Target hydration
70%
Bake temp
450°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 Spelt Hearth Loaf

Short autolyse (20 min). 2-3 GENTLE stretch-and-folds (spelt gluten tears easily). 3h bulk. Shape carefully, floured banneton, 6h cold retard. Bake in dutch oven 450°F: 20 min lid on, 18 min off.

Calculator pre-set to these values

Multiplier at 92°F
0.39×
Adjusted bulk ferment
1.2 h
Adjusted final proof
2.4 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); Peter Reinhart — Whole Grain Breads, Spelt chapter.