When It Goes Wrong
A flat, wide sourdough has lost structure at one of three points
A loaf that spreads into a disc instead of rising had the gas but not the container. Finding which stage failed takes one look at the crumb and one at the score.
What follows is an argument about flat sourdough loaves, and about where the received version of it stops being true.
The argument in brief
- Overproving, weak gluten and poor shaping all produce a flat loaf.
- The crumb pattern separates them.
- Hydration above your flour's capacity is a fourth possibility.
Three candidates, one symptom
A flat loaf means the dough could not hold the gas it generated, and there are only a few places where that ability comes from. It comes from gluten development, from fermentation being stopped at the right point, and from the surface tension built during shaping. A failure at any one of the three produces a loaf that spreads outward rather than rising, but they look different once cut.
Diagnosing which failed is what stops you adding folds to a dough that was actually overproved. Hydration beyond what the flour can support is a fourth cause that amplifies all three.
Overproved: flat with large upper holes
An overproved loaf spreads immediately when tipped from the banneton and holds almost no dome. The crumb typically shows a few very large holes near the top with a compressed, sometimes gummy layer at the base. The score barely opens, because the dough had no expansion left in reserve when it went into the oven.
The smell is sharply sour and alcoholic, and the surface is often blistered and slightly grey. The fix is to shorten bulk or the final prove, using an aliquot jar to stop at 50 to 75 per cent rise.
Weak gluten: flat with an even, tight crumb
A loaf that never developed enough gluten spreads for a different reason, which is that the network was never able to hold gas at all. The crumb is dense and fairly uniform, without the large upper holes of an overproved loaf, and it feels heavy rather than gummy. The dough will have felt slack throughout bulk and never gained the tension that folds normally build.
At oven temperature, check the flour protein content, add two or three sets of coil folds, and test with a windowpane before shaping. Very wholemeal doughs are prone to this, since bran physically cuts the gluten film as it develops.
Poor shaping: flat despite good crumb
A well fermented, well developed dough that was shaped loosely will still spread, because there was no taut skin directing the expansion upward. The crumb in this case often looks reasonably open and even, which is what makes the flat profile so frustrating. Preshape, rest for twenty to thirty minutes, then shape firmly on a lightly floured or bare bench so the dough can grip.
Weighed out, a heavily floured bench removes the friction that builds tension, which is a common and invisible mistake.
The surface should change from matte and slack to smooth and slightly glossy as tension builds, and that change is the cue.
Hydration beyond the flour
A dough at 85 per cent hydration made with a soft nine per cent protein flour cannot hold its shape however well it is handled. The flour simply does not have the protein to build a network strong enough for that much water. Drop the hydration by five per cent, or switch to a bread flour at twelve to thirteen per cent protein, and the same method will work.
There is no prize for a high hydration number, and a well made 70 per cent loaf beats a collapsed 85 per cent one every time. Raise hydration in five per cent steps across bakes, changing nothing else, so you can find your own ceiling.
Flour absorbs water differently by brand and by season; hydration is a target, not a rule.
Support during the bake
Even a correctly made high hydration dough benefits from sideways support in the first minutes of the oven. A preheated lidded pot constrains the loaf while the crust sets and gives a much taller result than an open tray. Baking in a tin is a legitimate answer for a dough that spreads, and it produces excellent bread rather than a compromise.
Weighed out, a very hot base from a stone or steel drives the expansion upward before the dough has time to flow outward. None of these fix a genuinely overproved dough, but they rescue a marginal one considerably.
The takeaway
Cut it open, look at the hole pattern, and fix the one stage the crumb is pointing at.
Bake it badly once on purpose. The failure teaches more than the photograph.
Questions readers ask
Should I add stronger flour or reduce the water first?
Reduce the water first, because it is a single change you can make immediately without buying anything. If a five per cent reduction fixes it, you have learned your flour's limit rather than just worked around it.
My dough looks fine until I tip it out, then it spreads. Why?
The banneton was holding the shape that the dough could not hold itself, which usually means overproving or insufficient shaping tension. A shorter final prove and a firmer shape are the two things to try.
