Bulk fermentation — the first rise from mixing to shaping — ends when the dough tells you, not the clock. But temperature determines how long that takes. With 20% starter and white bread flour, expect about 4–5 hours at 75°F (24°C), 6–8 hours at 70°F (21°C), and 9–12 hours at 65°F (18°C).
Fermentation rate roughly doubles with every 15°F (8°C) rise in dough temperature, per standard bread-science references. This table uses data from The Sourdough Journey’s controlled fermentation experiments (60+ test batches with King Arthur flour) and fermentcalculator.com’s guide.
Bulk Fermentation Time Table
White bread flour, 70% hydration. Times are for 50–75% volume rise.
| Dough temp | 10% starter | 20% starter | 30% starter |
|---|---|---|---|
| 65°F / 18°C | 12–16 hours | 9–12 hours | 7–9 hours |
| 68°F / 20°C | 10–14 hours | 7–9 hours | 5–7 hours |
| 70°F / 21°C | 9–12 hours | 6–8 hours | 5–6 hours |
| 72°F / 22°C | 8–10 hours | 5–7 hours | 4–5 hours |
| 75°F / 24°C | 6–8 hours | 4–5 hours | 3–4 hours |
| 78°F / 26°C | 5–6 hours | 3–4 hours | 2.5–3 hours |
| 80°F / 27°C | 4–5 hours | 3–4 hours | 2–3 hours |
| 85°F / 29°C | 3–4 hours | 2–3 hours | 1.5–2 hours |
These are starting estimates. Your starter’s strength and flour brand shift them. Use visual cues (below) to confirm readiness.
Four Signs Bulk Is Done
Use all four, not just one:
- Volume rise. Mark the starting level with a rubber band or tape. Done when risen 50–75%. Over 75% risks over-fermentation.
- Surface dome. Slightly convex, not flat. Small bubbles breaking through and visible tracking down the sides of the container.
- Jiggle test. Shake the bowl gently. The dough should wobble as one loose mass, like just-set jello. Stiff and barely moving = underfermented. Sloshing liquid-like = overfermented.
- Stretch test. Wet your hand and pull a piece from the edge. It should stretch far without tearing, feeling airy and extensible.
Never use the clock alone. A 75°F estimate can swing 30–60 minutes depending on starter health, flour brand, and how thoroughly you mixed.
Tracking Rise with an Aliquot Jar
An aliquot jar is a clean, straight-sided container (a small mason jar works well) where you set aside 50–75 g of dough immediately after mixing. Mark the starting level with a rubber band. The small piece ferments at the same rate as the main dough and is easier to measure because its sides are visible all around.
When the jar piece rises 50–75%, check the main dough with the four-sign test above to confirm. The jar method removes guesswork from volume tracking, particularly when your main container is wide or opaque.
Why Dough Temperature Beats Room Temperature
Friction from mixing and the heat of fermentation itself can push dough 2–4°F above ambient. If your kitchen reads 72°F but the dough thermometer reads 76°F, use the 76°F row — that is the actual environment the yeast and bacteria experience.
Measure with an instant-read probe inserted several inches into the center of the dough mass.
How Flour Type Shifts the Clock
| Flour | Adjustment vs. white bread flour |
|---|---|
| All-purpose | Slightly slower (lower enzyme activity) |
| White bread flour | Baseline |
| Whole wheat (20% blend) | ~15% faster |
| 100% whole wheat | ~25–30% faster |
| Rye (20% blend) | ~25% faster |
| 100% rye | ~30–40% faster |
If you bake with 20% whole wheat, subtract roughly 1 hour from the estimate in the table above at any given temperature.
Enriched Doughs Ferment More Slowly
The table above applies to lean doughs (flour, water, starter, salt only). Enriched doughs — those containing butter, eggs, milk, or significant sugar — ferment noticeably more slowly:
- Fat (butter, olive oil): Coats gluten strands and slows yeast activity. A dough with 10–15% butter may take 50–75% longer than the baseline table.
- Sugar (above 5% of flour weight): High sugar concentrations draw water away from yeast cells through osmosis, slowing fermentation. Enriched doughs like brioche or cinnamon roll dough may take 8–12 hours at 75°F.
- Eggs: Add protein and fat but have a modest slowing effect. Treat egg-enriched doughs as taking roughly 20–30% longer than the baseline.
For enriched doughs, use visual cues exclusively — the table times are a poor guide.
Stretch and Fold During Bulk
Most recipes include 3–4 sets of stretch-and-folds in the first two hours to build gluten strength. Space them 30 minutes apart; each set takes about 30 seconds. Stop when the dough holds its shape when lifted and feels noticeably more elastic. Leave it undisturbed after the final set until bulk is complete.
At High Temperatures (85°F+)
Above 85°F the bacteria get ahead of the yeast. The dough becomes sour faster and the window between properly fermented and over-fermented shrinks to under 30 minutes. If your kitchen is hot in summer, use cold water from the tap (or add a few ice cubes) to bring the initial dough temperature down to 75–78°F.
Cold Bulk Option
You can also run bulk in the fridge at 38–42°F for 8–16 hours. Fermentation continues slowly, building more complex flavor. Reduce your room-temperature bulk by about 60–70% first, then refrigerate. Shape cold; the firmer dough is easier to score.
Troubleshooting Bulk Fermentation
Dough spread flat after shaping. The most common sign of over-fermentation. The gluten weakened past the point of holding structure. Bake it — the loaf will be denser and flatter, but it is still edible. Next time, reduce bulk time by 30–45 minutes and check earlier.
Dough still stiff and won’t hold a dome after the expected time. Under-fermented. Continue bulk for another 1–2 hours and recheck. Cold flour (straight from a cold bag in winter) or a weak starter can both extend timing significantly.
Surface skin dried out during bulk. The container wasn’t sealed. Dried surface dough can’t stretch during shaping and creates a tough crust. Cover with plastic wrap or a damp towel and press it against the dough to prevent air contact.
Dough smells sharply sour or like alcohol. Fermentation ran too long. Acetic and lactic acid have built up beyond the ideal range. The bread can still be baked but will have a stronger, more sour flavor. Shorten bulk next time.
Use the sourdough schedule calculator to build a full timeline from feed to bake around your real dough temperature.