Cold Proofing Sourdough — Why It Works and How to Do It

Cold proofing (also called retarding) means placing your shaped sourdough loaf in the fridge for the final proof rather than proofing at room temperature. It's become the standard method for most home bakers, and for good reason — it improves nearly every aspect of the finished bread.

Why Cold Proof?

Refrigerating the shaped dough overnight produces several advantages:

• Better flavour: The slow, cool fermentation allows more complex acid development — particularly acetic acid, which adds depth without the sharpness of over-fermentation. Many bakers describe cold-proofed bread as having a more "developed" flavour than room-temperature proofed bread.
• Cleaner scoring: Cold dough is firm and easy to score cleanly. A soft, warm dough drags under the blade and tears. Cold dough gives the lame a clean surface to cut through.
• Flexible timing: You can shape the dough in the evening and bake any time the next morning. The fridge essentially pauses the fermentation until you're ready.
• Better crust: The temperature contrast between the cold dough and the preheated Dutch oven maximises oven spring and produces a more dramatic ear.

How to Cold Proof

1. Shape the loaf as normal and place it in the banneton, seam-side up.
2. Cover with a shower cap, plastic wrap, or a damp cloth — you want to prevent the surface from drying out.
3. Place in the fridge immediately after shaping — don't leave it at room temperature first unless the recipe specifically calls for it.
4. Proof in the fridge for 8–16 hours. For most home bakers, overnight (10–12 hours) is the sweet spot.

How Long Can You Cold Proof?

• Minimum: 4–6 hours (gives some benefit but not full flavour development)
• Optimal: 8–14 hours overnight
• Maximum: 18–20 hours (beyond this, the dough can over-ferment in the fridge and become slack)

The exact timing depends on how developed your dough was at the end of bulk fermentation. A dough that's slightly under-fermented before shaping will handle longer cold proofing better than one that was already well-fermented.

How to Tell If Cold-Proofed Dough Is Ready to Bake

After cold proofing, the dough should:

• Have increased in volume by 20–40% compared to when you put it in the fridge
• Feel firm and cold throughout
• Pass the poke test: poke with a floured finger. The indent should spring back slowly but not completely. If it springs back immediately, it needs more time. If it doesn't spring back at all, it's over-proofed.

Bake Straight From the Fridge

Don't let the dough warm up before baking. Take it straight from the fridge to the preheated Dutch oven. The temperature shock contributes to oven spring and helps produce a dramatic ear. The cold dough also scores more cleanly — score immediately after removing from the fridge.

Cold Proofing Without a Banneton

If you don't have a banneton, you can cold proof in a well-floured bowl lined with a floured cloth, or in a loaf tin. The principle is the same — shaped dough, covered, in the fridge overnight. A banneton produces better results because it supports the loaf shape and allows airflow, but the cold proofing benefits apply regardless of container.

For a complete walkthrough of the cold proofing process within a full sourdough recipe, see our Classic Sourdough Bread recipe. To get started with a proven starter culture, browse our sourdough starter kits.