Dough Dough Guides
How do you know when bulk fermentation is done? If one stage makes or breaks a loaf, it's the bulk ferment — and it's the one beginners get wrong most often, almost always by going off the clock instead of the dough. Here's exactly what I look for, and the simple trick that takes the guesswork out for good.
By Richard — I bake fresh sourdough every day in a kitchen that sits around 22–23°C, and I never judge a bulk rise by time alone. Watch the dough, not the clock.
What bulk fermentation is — and why it matters so much
The bulk ferment (or "bulk rise") is the long first rise after you've mixed your dough and before you shape it. It's where the dough gains its strength and structure, fills with gas, and develops most of its flavour. Get it right and everything afterwards is easy; get it wrong and no amount of good shaping or a hot oven will save the loaf. Most dense, gummy or flat loaves come down to a bulk that was cut short or left too long.
The signs it's actually done (not the clock)
A recipe that says "6 hours" is only ever a rough guide — your kitchen, your starter and your flour all change the timing. These are the signs I actually go by:
- Risen by about 30–50%. Not necessarily doubled — for most loaves, waiting for a full double tips you into over-proofed. A noticeable, confident rise is what you want.
- A domed, smooth top rather than a flat, slack surface.
- Bubbles on the surface and around the edges where the dough meets the bowl.
- It jiggles when you gently shake the bowl — it feels alive, airy and full of gas.
- It feels billowy and pulls away from the sides cleanly, not dense and claggy.
- It smells yeasty with a mild tang — not sharp, and no longer just of raw flour.
What it should smell like
Smell is the sign most people never think to use, and it is a good one. Ready dough smells pleasantly yeasty with a mild tang to it — think fresh beer, or plain yoghurt. If it still smells mostly of raw flour, fermentation has not got going yet and it needs more time. If it smells sharply sour, or faintly boozy, you have gone past the window: the acids have run away and the yeast is tiring.
The jar trick (my favourite shortcut)
This removes all the guesswork. When you start the bulk, pinch off a small sample of dough and press it into a straight-sided jar or glass. Mark the starting level with an elastic band or a marker, and let it rise alongside your main batch in the same spot. When the sample has climbed to your target — about 50% up — the whole batch is ready. You're measuring the rise directly instead of guessing. I use this constantly.
Temperature dictates everything
Bulk fermentation is really just a temperature game. Warmer dough ferments faster; cooler dough slower. That's why I mix to a target dough temperature of ~25°C (I check it with a probe thermometer and adjust my water temperature to hit it) and aim to bulk at 24–26°C. My cooler kitchen runs slower than most recipes assume, so I simply give it longer, or find a warmer spot — rather than panicking when the clock says it "should" be done.
How long it takes at each temperature
These are ballparks for a loaf built on roughly 500g of flour and 100g of starter. Treat them as a way to plan your day, not a target to bake to — they will be wrong for your kitchen by an hour or two in either direction, and that is normal.
| Dough temperature | Approximate bulk time |
|---|---|
| 20°C — a cool UK kitchen | 8–12 hours |
| 22–24°C — typical | 5–8 hours |
| 26°C — warm, or near the oven | 3.5–5 hours |
| 28°C — a summer heatwave | 2.5–4 hours |
If the table and the dough disagree, believe the dough.
Under-proofed vs over-proofed
Under-proofed
Dough feels tight and dense, smooth but not airy, with little rise. Bakes into a heavy, gummy loaf, often with a burst side seam as it tries to expand.
Over-proofed
Dough is very slack, loose, almost soupy, wildly bubbly and blistered, with no structure left. Bakes flat and spreading, with no spring and a sharper, sourer taste.
You're aiming for the middle: risen, domed and airy, but still holding its shape and with some tension left to it.
The poke test (after shaping and proof)
Flour a finger and gently press into the dough about a centimetre. If it springs back slowly and only part-way, leaving a slight dent, it's ready. If it springs back instantly and completely, it needs more time. If it doesn't spring back at all and the dent stays, it's over-proofed — bake it now and shorten things next time.
Finishing bulk in the fridge
Plenty of bakers cut the room-temperature bulk short and finish the dough overnight in the fridge — the classic cold retard. The cold slows the yeast right down while the bacteria carry on working, which builds a deeper flavour and a chewier crust. If you are going to retard, stop the room-temperature bulk a little earlier than you otherwise would, at around 30–40% risen rather than the full 50%, because the dough keeps fermenting slowly in the cold.
Common bulk-fermentation mistakes
- Going by the clock. The number one error. Your kitchen is not the recipe's kitchen.
- A cold kitchen. Dough at 18°C can take twice as long as the recipe says — that's normal, not a failure.
- Using a sluggish starter. If it wasn't bubbly and at its peak, the bulk will crawl. Check it floats first.
- Waiting for a full double. For most loaves, that's too far. Trust the 30–50% range.
Once your dough is properly fermented, it's ready to shape. And if a loaf still comes out dense or flat, my loaf troubleshooting guide will tell you which way you missed.
Bulk fermentation questions
How do I know when bulk fermentation is done?
Use the signs together rather than relying on any one: a rise of about 30–50%, a domed and smooth top, bubbles on the surface and around the edges of the bowl, a jelly-like jiggle when you shake it, and a billowy feel as it pulls cleanly away from the sides. The jar trick gives you the rise as an actual measurement instead of a guess.
Should the dough double during bulk fermentation?
Usually not. For most loaves a full double takes you past the window and into over-proofed. Aim for 30–50%. A doubled dough is not automatically ruined, but it is harder to shape and far easier to overdo.
How long does bulk fermentation take?
It depends almost entirely on dough temperature — see the table above. At 22–24°C, expect roughly 5–8 hours for a typical loaf. A cool kitchen at 20°C can stretch that to 8–12 hours, and a warm one at 26°C can bring it down to 3.5–5. Judge by the dough, not the clock.
What does over-proofed dough look like?
Very slack and loose, almost soupy, wildly bubbly and blistered, sometimes with a collapsed or pockmarked top. It will not hold its shape when you tip it out, and it smells sharply sour or slightly boozy. In the oven it spreads flat with no spring.
Can I bulk ferment sourdough in the fridge?
Yes — that is the cold retard. Bulk at room temperature until the dough is around 30–40% risen, then move it to the fridge for 8–24 hours. It carries on fermenting slowly in the cold and develops a deeper flavour without tipping over the edge.
What if my bulk fermentation is going too fast?
Usually a warm kitchen, or a starter used right at its peak. Move the dough somewhere cooler for the last stretch of bulk, use a little less starter next time, or simply plan for a shorter bulk overall.
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Bulk fermentation is easier with a lively starter
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