Shaping Sourdough and the Cold Retard
Pre-shape, rest, final shape, and then twelve to sixteen hours in the fridge. The retard is where the loaf gets its flavour — and where fermentation finishes the job that makes this bread the exception.
ON THIS PAGE · 5 SECTIONS
After bulk fermentation, sourdough is shaped twice — a loose pre-shape, a twenty-minute rest, then a tight final shape — and placed seam-up in a floured basket. It then goes into the fridge for twelve to sixteen hours. This cold retard slows the yeast almost to a stop while the lactic acid bacteria keep working, which deepens the flavour, makes the loaf easier to score, and continues the phytate breakdown that is the whole reason we eat this bread.
Pre-shape and bench rest
Turn the dough out onto a lightly floured surface. Using a bench scraper, fold the edges into the centre a few times to make a loose round, then flip it seam-down and leave it uncovered for twenty minutes. The surface will dry very slightly and the gluten will relax, which is what makes the final shape possible.
Do not flour heavily. A little stickiness is what lets the dough grip the surface and build tension in the next step.
Final shape
Flip the round seam-up. Fold the bottom third up over the middle, then each side in, then roll the whole thing down from the top so the seam ends underneath. Cup both hands behind it and drag it toward you across the bench a few times — the surface should tighten into a smooth, taut skin with no tears.
Place it seam-up in a well-floured banneton or a bowl lined with a floured tea towel. Rice flour is the one to dust with: it does not absorb water, so the loaf will not stick after a night in the fridge.
How long to retard
Everything in the fridge happens at roughly 4°C, so this table does not move with your kitchen. Yeast activity almost stops; the bacteria slow but keep going, and that asymmetry is the point.
| Fridge time | Flavour | Crust and scoring | Notes |
|---|---|---|---|
| 8 h | Mild, slightly sweet | Soft skin, harder to score cleanly | The minimum. Fine if you must bake early. |
| 12–16 h | Balanced, clearly sour | Firm, cold, scores cleanly | The target. Bake straight from the fridge. |
| 20–24 h | Pronounced, tangy | Still firm | Good if you like it sour. Watch for the surface drying out. |
| 36 h+ | Sharp, sometimes flat | Skin may tear; loaf may spread | Over-retarded. The gluten begins to break down. |
Why the fridge matters more than it looks
Part 1 made the argument that this bread is the exception to the grain rule because fermentation degrades most of the phytate and pre-digests much of the gluten. Most of that work happens in the bulk — but a good share of it happens here, overnight, while the yeast is asleep and the bacteria are not.
That is why a same-day sourdough, bulked and baked in six hours, is not quite the same food. It has the shape. It has less of the reason.
Before Part 5
Put the Dutch oven in the oven and heat both to 250°C for at least forty-five minutes before the loaf comes out of the fridge. A cold pot is the second most common reason a first loaf fails.
