How to Proof Sourdough: Times, Poke Test & Cold Proof

Proofing is the final rise before baking — the last chance for the shaped loaf to fill with gas before it hits the oven. Get it right and the loaf springs upward, scores open cleanly, and bakes with an open, airy crumb. Get it wrong and even a perfectly shaped loaf will bake flat, dense, or gummy.

This guide covers how long the final proof takes, how to read the dough with the poke test, and how cold proofing in the fridge builds flavour and makes scoring easier.

What Proofing Actually Is

Proofing (the final proof) is the rise that happens after shaping and before baking. The shaped loaf sits in its banneton while the wild yeast continues to produce carbon dioxide, inflating the dough one last time.

It is easy to confuse proofing with bulk fermentation, but they are different stages:

• Bulk fermentation is the first, longer rise of the whole batch of dough, before shaping. This is where most gas and flavour develop and where the gluten strengthens.
• Proofing is the shorter final rise of the shaped, individual loaf. It tops up the gas and sets the final volume just before baking.

Because most of the fermentation work happens during bulk, the final proof is usually much shorter. If bulk was taken far enough, the loaf only needs a modest final rise. If bulk was cut short, the proof carries more of the load and runs longer.

How Long Does Proofing Take?

There is no single number, because proof time depends on temperature, starter strength, hydration, and how far bulk fermentation was pushed. As a rough guide:

• Room temperature (about 21°C / 70°F): 2–4 hours for the final proof.
• Warm kitchen (26°C / 78°F+): as little as 1–2 hours — watch it closely.
• Cold proof in the fridge (about 4°C / 38°F): 12–48 hours, most commonly overnight.

Temperature is the biggest lever. Fermentation roughly doubles in speed for every 8–10°C rise, so a warm kitchen can halve your proof time and a cold fridge can stretch it into a day or more. Treat clock times as starting points, not rules — always confirm with the dough itself.

The Poke Test

The poke test is the most reliable way to judge proof, because it reads the actual state of the dough rather than the clock.

How to do it:

1. Lightly flour a fingertip.
2. Press it gently into the shaped dough, about 1 cm deep.
3. Watch how the dent recovers.

How to read it:

• Springs back slowly, leaving a slight indent → ready to bake. The dough has enough gas and gluten structure to rise in the oven but hasn’t gone past its peak.
• Springs back instantly and fully → underproofed. The dough needs more time. Give it another 20–30 minutes and test again.
• Doesn’t spring back at all; feels slack and the dent stays → overproofed. The gluten has weakened. Bake it now (or turn it into a pan loaf) and shorten the proof next time.

The poke test takes practice. Combine it with a visual check: a ready loaf usually looks noticeably puffed, has grown by roughly 30–50%, and jiggles slightly when the basket is nudged.

Cold Proofing (Retarding)

Cold proofing — also called retarding — means moving the shaped loaf into the fridge for its final proof instead of leaving it on the counter. It is optional, but many bakers use it every bake for three reasons:

• Flexibility. Cold slows fermentation to a crawl, so a loaf can sit in the fridge for 12–18 hours (and often longer) without overproofing. You bake when it suits you, not when the clock dictates.
• Flavour. The long, cold rise lets acids develop slowly, giving a deeper, more complex, slightly tangier flavour than a fast room-temperature proof.
• Scoring and shape. Chilled dough firms up, so the surface is easier to score cleanly and the loaf holds its shape as it goes into the oven.

How to cold proof: Shape the loaf, place it seam-side up in a floured banneton, cover it (a bag or shower cap works), and refrigerate. Most bakers bake straight from the fridge — no need to bring the loaf back to room temperature first, which also helps keep the surface firm for scoring.

Underproofed vs Overproofed

Reading the two failure modes helps you correct course.

Underproofed dough hasn’t risen enough. It springs back fast on the poke test, feels dense, and bursts unpredictably in the oven — often tearing at the sides rather than opening at the score. Fix it by giving the loaf more time before baking.

Overproofed dough has fermented past its peak. It fails the poke test (no spring-back), spreads flat, and bakes dense and gummy with weak oven spring. Overproofing usually starts upstream in bulk fermentation, so if your loaves are consistently overproofing, look there first. Our guide to overproofed sourdough covers the signs and rescues in detail.

When in doubt, err slightly toward underproofing. A slightly underproofed loaf still springs and bakes well; an overproofed one rarely recovers.

Proofing and the Rest of the Process

Proofing sits at the end of a chain, and it depends on everything before it. If bulk fermentation was taken to the right point and the loaf was shaped with good tension, the final proof is short and predictable. If bulk ran short or long, the proof has to compensate and becomes much harder to judge.

Hydration matters too: wetter doughs spread faster and can look overproofed sooner. If your loaves proof unevenly or spread flat, use the hydration calculator to dial in a slightly firmer dough next time.

Nail the poke test and lean on a cold overnight proof, and the final rise stops being guesswork — it becomes the reliable, flavour-building last step before a well-sprung loaf.

FAQs

How long should sourdough proof? The final proof at room temperature (around 21°C / 70°F) usually takes 2–4 hours, but it depends on temperature, starter strength, and how far bulk fermentation was taken. A cold proof in the fridge runs 12–48 hours. Judge readiness by the poke test rather than the clock.

What is the poke test for sourdough? Press a floured finger about 1 cm into the shaped dough. If the dent springs back slowly and leaves a slight indent, it’s ready. If it springs back instantly, it needs more time. If it doesn’t spring back at all and feels slack, it’s overproofed.

Should I proof sourdough in the fridge? Cold proofing the shaped loaf is optional but very useful. It slows fermentation for a wide baking window, deepens flavour, and firms the surface so the loaf is easier to score. Most bakers cold proof overnight and bake straight from the fridge.

Can you proof sourdough too long? Yes. Overproofing means the dough has fermented past its peak — the gluten weakens, the dough spreads, and the poke test shows no spring-back. Overproofed loaves bake flat and gummy. Cutting the proof short or baking from a cold retard helps avoid it.

What is the difference between bulk fermentation and proofing? Bulk fermentation is the first, longer rise of the whole batch before shaping. Proofing is the shorter final rise of the shaped loaf before baking. Both are fermentation, but proofing sets the individual loaf’s final volume.

Can I proof sourdough overnight on the counter? It’s risky — at room temperature an overnight proof usually overproofs unless your kitchen is very cold. For an overnight final proof, use the fridge. Counter proofing suits shorter 2–4 hour windows where you can watch the dough.