Temperature reference

73–77°F Sourdough (22.80–25.00°C)

Bulk multiplier: 1.000× · Proof multiplier: 1.000× · Activity: active

Dial shows where 73–77°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

BASELINE — the reference temperature for all fermentation times in this system. Warm kitchen, proofing box, summer AC setting. 76°F (24.4°C) is the classical bakery target. If you control dough temperature via dough desired temperature (DDT) calculations, aim for this range. All published recipe times assume this temperature unless otherwise noted.

Why 73–77°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 73–77°F the net effect is a 1.00× bulk and 1.00× proof multiplier versus the 76°F bakery baseline, so every stage runs on baseline. 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 73–77°F

Fermentation stage timing at 73–77°F versus the 76°F baseline
Stage	At 76°F baseline	At this temperature
Bulk ferment (typical 4h)	4 h	4 h
Final proof	2.5 h	2.5 h
Levain to peak	5 h	5 h

Representative country-loaf baselines multiplied by this range's bulk (1.00×) and proof (1.00×) factors. Treat these as a floor to start checking, not a finish line.

What to watch for at 73–77°F

This range sits close to the 76°F bakery baseline, so printed recipe times apply almost directly — the usual bulk-and-proof cues hold with only minor adjustment. Still judge the dough by rise and feel rather than the clock; every kitchen has cold and warm spots.

How to adjust your formula at 73–77°F

Keep your usual 15–20% levain — the modest 1.00× shift is best handled by watching the dough rather than re-formulating.

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 73–77°F, sooner or later by the 1.00× factor above.

73–77°F sourdough — FAQ

How does a 73–77°F kitchen change sourdough timing?

Fermentation runs 1.00× the 76°F bakery baseline (on baseline). A recipe's printed 4-hour bulk becomes roughly 4 hours here, and a 2.5-hour proof becomes about 2.5 hours. Printed times only hold at the temperature they were written for.

How much longer or shorter is bulk fermentation at 73–77°F?

Multiply your recipe's baseline bulk time by 1.00. A typical 4-hour country-loaf bulk becomes about 4 hours at 73–77°F. The multiplier comes from Modernist Bread's temperature chapter.

What's the biggest mistake at 73–77°F?

There's no strong temperature trap here. This range sits close to the 76°F bakery baseline, so printed recipe times apply almost directly — the usual bulk-and-proof cues hold with only minor adjustment. Still judge the dough by rise and feel rather than the clock; every kitchen has cold and warm spots.

Should I change my levain percentage at 73–77°F?

Keep your usual 15–20% levain — the modest 1.00× shift is best handled by watching the dough rather than re-formulating.

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 73–77°F those cues arrive in a different amount of time than a recipe assumes — the cues themselves don't change.

Is 73–77°F a good kitchen temperature for sourdough?

Timing calculator at this temperature

Bulk (at 76°F)(h)

Proof (at 76°F)(h)

Your kitchen temp(°F)

Multiplier at 75°F: 1.05×
Adjusted bulk ferment: 4.2 h
Adjusted final proof: 12.6 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 73–77°F:

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 73-77°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)
Baker's percentage is by weight, not volume — a 0.1 g scale is what makes the math on this page accurate.
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Dutch oven / combo cooker
Traps steam for the first bake phase — the single biggest factor in oven spring and a blistered, glossy crust.
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Banneton proofing basket
Wicks moisture and holds shape during the final proof, so high-hydration dough doesn't spread flat.
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Bread lame + bench scraper
A sharp lame scores clean ears; a steel bench scraper handles wet, sticky dough without tearing the gluten.
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High-protein bread flour
The math assumes ~12–14% protein. Real bread flour absorbs the hydration you calculate — all-purpose won't.
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Danish dough whisk
Mixes shaggy, high-hydration dough in seconds without the gluey mess of a spoon or your hands.
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🎧 Or learn the craft by ear

The numbers here are the what; a good baking book is the why. An Audible trial gets you any title free — Michael Pollan’s Cooked(the “Air” chapter is the best story ever told about why bread rises) is a perfect first listen.

Start a free Audible trial →

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Gear guides — what actually matters