Sourdough guide

Sourdough Bulk Fermentation at 68, 70, 72, 75 and 78°F

By Bakers Percent editorial10 min readLast updated October 23, 2026Researched guide, AI-assisted (how we make these)

How this guide was made: it is a researched guide compiled from the published sources listed at the end of this page. We compare what those sources say and do the arithmetic; we don't claim to have baked these loaves. Each instruction is attributed so you can check it.

Most kitchens do not sit at 65 or 80°F. They sit at 68, 72 or 75°F, and the published chart that most bakers lean on only prints a row every 5 or 10 degrees. This page reads that chart at the five dough temperatures people actually ask about, says plainly which of the five numbers are published and which are our own straight-line fill-ins, and then sets each one next to what other recipes report near the same temperature. Our main bulk fermentation guide covers what bulk is and how to tell it is done; this page is for the question "my dough is at X degrees, how long?"

How to read this page

The figures come from one source, the Sourdough Archive bulk fermentation chart [1]. It gives a dough-temperature row every 5°F from 65°F to 85°F, assumes 20% starter as a percentage of flour, and also gives a rise target for each row. Its own rule of thumb is that every 10°F drop roughly doubles the bulk time [1]. We use only that chart for the times, because it gives a row every 5°F across the range in one place, with the starter amount stated. Every other source in this guide gives one recipe at one temperature, or only a few temperatures.

70°F and 75°F are rows in the chart. 68, 72 and 78°F are not. For those we take the two neighbouring rows and draw a straight line between them. For example, 72°F is two-fifths of the way from the 70°F row to the 75°F row, so the low end is 6 − 0.4 × 2 = 5.2 hours and the high end is 9 − 0.4 × 3 = 7.8 hours. The "planner plan" column below is the midpoint of that range, rounded to the nearest 5 minutes, which is what the planner puts in your schedule.

The five temperatures at a glance

For the rise column we print the neighbouring published rows rather than inventing a figure in between. The "same-day warning" is the bake planner's own rule: when the published bulk time is already 6 hours or more, it tells you a same-day bake is a stretch.

At 68°F: the winter kitchen

At 68°F the chart puts bulk at roughly 7 to 10 hours, and the other published recipes run longer still. The Clever Carrot's recipe takes about 10–12 hours at 68°F in winter, with about 150 g of starter [7]. British Sourdough's chart gives 12–16 hours for a dough at 18–20°C (64–68°F) with its own recipe [8]. The gap between these and the chart is not a contradiction: the sources use different starter amounts and different flours, and the chart's numbers assume 20% starter [1]. Treat 68°F as "most of a day unless you add starter or warm the dough".

• If you mix at 8:00 am: the midpoint lands at 4:30 pm; the whole range runs from 2:48 pm to 6:12 pm.
• What helps: warm the dough rather than the room. King Arthur gives 75–78°F as the ideal range for wheat doughs and says the same range suits sourdough [10]. In a 68°F kitchen our bulk guide's worked example uses 100°F water to reach a 78°F dough, with the flour at 68°F, the starter at 70°F and 6°F of mixing friction.
• Rise target: between the chart's 65°F row (75–100%) and 70°F row (50–75%) [1]. A cool dough is meant to grow more before you stop.
• Planner note: the planner warns that a same-day bake at this temperature is a stretch, because the published time alone is more than 6 hours.

At 70°F: the edge of overnight on the counter

70°F is a published row: 6–9 hours [1]. It is also the temperature The Pantry Mama uses as its dividing line. Its overnight loaf is for a room around 21°C (about 70°F) or cooler, and it starts with a smaller amount of starter, about 50 g in its recipe [9]. Its timeline runs from about 11 pm to 7 am, an 8-hour bulk.

• If you mix at 10:00 pm for an overnight counter bulk: the range ends between 4:00 am and 7:00 am, with the midpoint at 5:30 am. A dough with the chart's 20% starter mixed at that hour would finish in the small hours, and overnight recipes such as The Pantry Mama's use less starter [9].
• Rise target: 50–75% [1].
• What other recipes say: King Arthur's "typical" 3–5 hours is given for room temperature without naming one [3], so do not read it as a figure for 70°F.
• Planner note: the same-day warning triggers here, because the low end of the range is exactly 6 hours.

At 72°F: the average kitchen

72°F is not a printed row. Our fill-in is 5 h 12 min–7 h 48 min, with a planner midpoint of 6 h 30 min. This is the temperature where published sources visibly disagree, so it is a good place to see the spread. British Sourdough gives about 9 hours at 22°C (72°F) for its recipe [8], above the top of our range, while the chart's own neighbouring rows imply roughly 6½ hours [1]. The reasons are the ones in the main guide: starter amount, flour and how warm the dough really is. The clock cannot settle it.

• If you mix at 8:00 am: the midpoint lands at 2:30 pm, and the range runs 1:12 pm to 3:48 pm. A morning mix and an afternoon shape is realistic without a night shift.
• What helps: our bulk guide's average-kitchen example uses room, flour and starter at 72°F, 72°F and 74°F with 88°F water to reach a 78°F dough.
• Rise target: between 50–75% (70°F row) and 30–50% (75°F row) [1].
• Planner note: no same-day warning, because the low end (5 h 12 min) is under 6 hours.

At 75°F: the reference row

75°F is a published row and the one most recipes quote: 4–6 hours [1]. Because it is the common case, it is also where the most independent figures exist, and they sit comfortably at or below the chart's range: The Perfect Loaf's weekday loaf takes about 3.5 hours at 75°F dough [5], Country Roads Sourdough's same-day loaf about 4 hours with extra starter on purpose [6], and King Arthur says 3–5 hours is typical at room temperature [3]. The chart shows one reason for the spread, below: starter amount moves the answer as much as temperature does.

• If you mix at 8:00 am: the midpoint lands at 1:00 pm; the range runs from 12:00 pm to 2:00 pm. The same-day timeline in our overnight guide ends bulk at about 12:00 noon for the same mix time, following Country Roads [6].
• Starter amount moves the answer as much as temperature does. At the same 75°F, the Sourdough Archive chart runs from 8–12 hours with 5% starter to 2–4 hours with 30% or more [1].
• Rise target: 30–50% [1].
• Planner note: no same-day warning.

At 78°F: warm and quick

78°F is not a printed row. Our fill-in is 3 h 24 min–4 h 48 min, planner midpoint 4 h 05 min. Published figures here are close to it. The Perfect Loaf's bulk guide gives 2–5 hours for a 74–78°F dough [2], its Beginner's Sourdough recipe aims for a 78°F dough [4], and British Sourdough gives about 5 hours at 26°C (79°F) for its recipe [8].

• If you mix at 8:00 am: the midpoint lands at 12:05 pm; the range runs 11:24 am to 12:48 pm. With a window that narrow, start checking the dough early.
• Warm dough keeps going in the fridge. The Sourdough Archive chart aims for a smaller rise in warm dough, 25–30% at 80°F, and explains that warm dough keeps fermenting for hours while it cools, so it should go in the fridge earlier [1]. The neighbouring rows here are 30–50% at 75°F and 25–30% at 80°F.
• If your kitchen is warm: the guide's warm-kitchen example (room 82°F, flour 80°F, starter 82°F) uses 62°F water to land at 78°F.
• Upper limit: The Perfect Loaf would not go above about 85°F [2].

What if your dough is at 73°F, or 66°F?

Do what we did: find the two rows on either side and draw a straight line. At 73°F, for example, you are three-fifths of the way from 70°F to 75°F, so the low end is 6 − 0.6 × 2 = 4.8 hours and the high end is 9 − 0.6 × 3 = 7.2 hours: 4 h 48 min–7 h 12 min. Outside 65–85°F the chart ends, so the bake planner uses the nearest row and warns you rather than guess: cooler dough than the 65°F row will take longer than 8–12 hours, and warmer dough than the 85°F row moves faster than 2–3 hours [1].

A worked example from the bake planner

Say it is 75°F in the kitchen, you get home on Friday at 5:00 pm, and you would like to slice bread on Saturday at 1:15 pm. The bake planner counts backward from the ready time, using the 75°F row's 4–6 hours (midpoint 5 hours) for bulk:

Every duration other than bulk comes from a published figure or the midpoint of a published range, explained on the planner page along with its sources. Run the same ready-by time at 70°F instead and bulk grows to 7 h 30 min, which pushes the starter feed back to 3:30 am: that is the planner's "middle of the night" warning at work.

The distinct thing each temperature teaches

• 68°F: published recipes run longer than the chart, so plan on most of a day or add starter.
• 70°F: the edge of overnight counter bulk, and why those recipes use less starter [9].
• 72°F: the temperature where published sources disagree most, which shows why the dough, not the clock, decides.
• 75°F: the reference row, and a reminder that starter amount matters as much as temperature [1].
• 78°F: the narrowest window, where you need to start checking early and plan for the fridge.

For the signs that tell you bulk is finished, the poke-test mistake, and the cold-bulk and overnight options, read the full bulk fermentation guide. To hit a dough temperature on purpose, use the water temperature calculator; to scale a recipe once you have your timing, try the recipe builder.

FAQ

How long is sourdough bulk fermentation at 72°F? The Sourdough Archive chart has no 72°F row. Drawing a straight line between its 70°F row (6–9 hours) and its 75°F row (4–6 hours) gives about 5 hours 12 minutes to 7 hours 48 minutes for a dough with 20% starter. That is our estimate, not a published figure [1].

How long is bulk fermentation at 70°F? The chart's 70°F row says 6–9 hours for a dough with 20% starter, with a target rise of 50–75% [1].

How long is bulk fermentation at 75°F? The chart says 4–6 hours with 20% starter and a rise of 30–50% [1]. Individual recipes often finish sooner: about 3.5 hours for The Perfect Loaf's weekday loaf [5] and about 4 hours for Country Roads Sourdough's same-day loaf [6].

Is the table by room temperature or dough temperature? Dough temperature [1]. The same chart notes that two kitchens at the same air temperature can produce doughs 10°F apart, depending on the water used.

Why do other recipes give different times at the same temperature? They use different amounts of starter and different flours. At 75°F the same chart runs from 8–12 hours with 5% starter to 2–4 hours with 30% or more [1].

Sources (checked 2026-10-23)

1. Sourdough Archive, "Sourdough Bulk Fermentation Chart: Complete Temperature + Time Guide": https://sourdougharchive.com/sourdough-bulk-fermentation-chart/
2. The Perfect Loaf (Maurizio Leo), "The Ultimate Guide to Bread Dough Bulk Fermentation" (updated 2026-04-16): https://www.theperfectloaf.com/guides/the-ultimate-guide-to-bread-dough-bulk-fermentation/
3. King Arthur Baking (Maurizio Leo), "Bulk fermentation, explained" (2019-07-22): https://www.kingarthurbaking.com/blog/2019/07/22/bulk-fermentation
4. The Perfect Loaf, "Beginner's Sourdough Bread" (updated 2026-01-15): https://www.theperfectloaf.com/beginners-sourdough-bread/
5. The Perfect Loaf, "Simple Weekday Sourdough Bread": https://www.theperfectloaf.com/simple-weekday-sourdough-bread/
6. Country Roads Sourdough, "Same Day Sourdough Bread": https://countryroadssourdough.com/same-day-sourdough-bread/
7. The Clever Carrot, "Sourdough Bread: A Beginner's Guide": https://www.theclevercarrot.com/2014/01/sourdough-bread-a-beginners-guide/
8. British Sourdough, "Bulk Fermentation for Sourdough: Using Temperature Not Time" (2026-04-17): https://britishsourdough.com/bulk-fermentation-for-sourdough-using-temperature-not-time/ (last read 2026-10-17; the site blocks automated checks, so it was not re-checked on 2026-10-23)
9. The Pantry Mama, "Overnight Sourdough Bread": https://pantrymama.com/overnight-sourdough-bread/
10. King Arthur Baking, "Desired dough temperature" (2018-05-29): https://www.kingarthurbaking.com/blog/2018/05/29/desired-dough-temperature