Temperature reference
78–82°F Sourdough (25.60–27.80°C)
Bulk multiplier: 0.750× · Proof multiplier: 0.750× · Activity: very-active
Dial shows where 78–82°F sits on the sourdough activity scale (32–100°F). Indicator points at the midpoint; color shifts from cool blue (dormant) to warm orange (hyperactive).
Recommendation
Warm kitchen or proofing box — ideal for accelerating fermentation. Ferment 25% faster than baseline. Good for schedule compression. Watch carefully — dough over-proofs quickly. Ideal for hot-weather baking when you want to get dough into cold retard before too much fermentation happens. Consider reducing levain to 12-15% to slow things back down.
Why 78–82°F changes your timing
Sourdough is a living culture, and its yeast and bacteria speed up as it warms. Across the useful baking window (roughly 50–95°F) the rate follows the classic Q10 relationship — fermentation runs about two to three times faster for every ~15–18°F of warming. At 78–82°F the net effect is a 0.75× bulk and 0.75× proof multiplier versus the 76°F bakery baseline, so every stage runs faster. That single number is why a formula's printed times only hold at the temperature they were written for — move the dough 10 degrees and the clock is wrong.
Worked timing at 78–82°F
| Stage | At 76°F baseline | At this temperature |
|---|---|---|
| Bulk ferment (typical 4h) | 4 h | 3 h |
| Final proof | 2.5 h | 1.9 h |
| Levain to peak | 5 h | 3.8 h |
Representative country-loaf baselines multiplied by this range's bulk (0.75×) and proof (0.75×) factors. Treat these as a floor to start checking, not a finish line.
What to watch for at 78–82°F
Fermentation runs fast here, so the common failure is over-proofing — the dough balloons, then loses its spring and bakes up flat with a pale, gummy crumb. Set a timer as a floor, not a target, and start checking the dough by feel and jiggle early.
How to adjust your formula at 78–82°F
Because the culture is very-active at this temperature, drop your levain to about 10–15% and keep the bulk short so the fast rise doesn't out-run gluten development — otherwise the crumb goes gummy and the loaf spreads.
To land the dough in this range even when the room swings, use the desired-dough-temperature (DDT) method: dough temperature ≈ (flour temp + room temp + water temp + friction factor) ÷ 4. Solve for the water temperature you need — in a cool kitchen use warmer water; in a hot one, cool or even iced water — so the dough itself, not just the air, sits at your target.
Telling doneness by feel, not the clock
The times above are a guide; the dough is the real timer. Bulk is done when the mass has risen 50–75%, looks domed and bubbly, and jiggles like set custard when you shake the container — an aliquot jar (a small sample in a straight-sided container) makes the rise easy to read. The final proof is ready when a floured poke springs back slowly and only partway. These cues are identical at every temperature; only when they arrive changes — at 78–82°F, sooner or later by the 0.75× factor above.
78–82°F sourdough — FAQ
How does a 78–82°F kitchen change sourdough timing?
Fermentation runs 0.75× the 76°F bakery baseline (faster). A recipe's printed 4-hour bulk becomes roughly 3 hours here, and a 2.5-hour proof becomes about 1.9 hours. Printed times only hold at the temperature they were written for.
How much longer or shorter is bulk fermentation at 78–82°F?
Multiply your recipe's baseline bulk time by 0.75. A typical 4-hour country-loaf bulk becomes about 3 hours at 78–82°F. The multiplier comes from Modernist Bread's temperature chapter.
What's the biggest mistake at 78–82°F?
The main risk is over-proofing. Fermentation runs fast here, so the common failure is over-proofing — the dough balloons, then loses its spring and bakes up flat with a pale, gummy crumb. Set a timer as a floor, not a target, and start checking the dough by feel and jiggle early.
Should I change my levain percentage at 78–82°F?
Because the culture is very-active at this temperature, drop your levain to about 10–15% and keep the bulk short so the fast rise doesn't out-run gluten development — otherwise the crumb goes gummy and the loaf spreads.
How do I tell my dough is ready instead of using the clock?
Watch the dough, not the timer: a well-fermented bulk rises 50–75% and jiggles when you shake the container; a well-proofed loaf springs back slowly and only partway when poked (the "poke test"). At 78–82°F those cues arrive in a different amount of time than a recipe assumes — the cues themselves don't change.
Is 78–82°F a good kitchen temperature for sourdough?
Warm kitchen or proofing box — ideal for accelerating fermentation. Ferment 25% faster than baseline. Good for schedule compression. Watch carefully — dough over-proofs quickly. Ideal for hot-weather baking when you want to get dough into cold retard before too much fermentation happens. Consider reducing levain to 12-15% to slow things back down.
Timing calculator at this temperature
- Multiplier at 80°F
- 0.78×
- Adjusted bulk ferment
- 3.1 h
- Adjusted final proof
- 9.4 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.
How each style behaves at this temperature
Click any style to see its full timing at 78–82°F:
- Country Loaf (Pain de Campagne)
- Ciabatta
- Baguette
- Focaccia
- Sourdough Brioche
- 100% Rye Pan Loaf
- 40% Rye Hearth Loaf
- 100% Whole Wheat Pan Loaf
- Spelt Hearth Loaf
- Pain de Campagne (Variant with Rye)
- Sourdough Bagel
- Sourdough Pretzel
- Neapolitan Pizza (Sourdough)
- NY Style Pizza (Sourdough)
- Focaccia Genovese
- Pain au Levain
- Miche (Poilâne-Style)
- Pan de Cristal
- Ciabatta Integrale
- Sourdough English Muffin
- Sourdough Naan
- Sourdough Tortilla
- Sourdough Challah
- Sourdough Panettone
- Hokkaido Milk Bread (Sourdough)
Related references on this site
- Guide: temperature and time in sourdough — the piecewise-linear multipliers and how to use them in planning
- Autolyse strategy by temperature — warmer kitchen needs shorter autolyse before adding starter
- Levain build timing — how long to wait before peak in a hot vs cold kitchen
- All 25 recipes — each has a /timing page — each recipe shows bulk + proof at 78-82°F
- All 12 hydration levels — drier doughs ferment slower; combine hydration choice with temperature
- All 8 temperature ranges — from cold retard 38-40°F to peak summer 88-95°F
The gear that makes the math work
A short, honest baking kit. The scale matters most — every weight on this page is in grams. The Dutch oven is what turns a good crumb into a great crust.
- Digital kitchen scale (0.1 g)View on Amazon →
- Dutch oven / combo cookerView on Amazon →
- Banneton proofing basketView on Amazon →
- Bread lame + bench scraperView on Amazon →
- High-protein bread flourView on Amazon →
- Danish dough whiskView on Amazon →
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