Troubleshooting Flat Sourdough Loaves

A flat loaf isn't just disappointing — it's diagnostic. Six things cause flat bread; identify which is yours and fix it.

1. Over-fermentation

The most common cause. The dough's gluten has weakened past the point where it can hold a shape.

Signs — dough spreads when turned out; doesn't hold form during bench rest; over-sour smell.

Fix — reduce bulk fermentation time; reduce starter percentage; cooler environment.

2. Under-shaped

The dough doesn't have enough surface tension to hold its dome shape during the final proof and bake.

Signs — dough looks slack in the banneton; spreads out instead of holding upward; the seam reopens.

Fix — more aggressive shaping with more tension. Pre-shape, bench rest, then final shape with confidence. Use the bench scraper to drag the dough across the counter, building tension.

3. Hydration too high

Your gluten can't support the water content.

Signs — wet, sticky dough at every stage; impossible to shape cleanly; spreads immediately.

Fix — drop hydration 5%. Master that, then go back up.

4. Weak gluten

Either underdeveloped or weakened by acidic over-fermentation or weak flour.

Signs — dough tears easily during shaping; windowpane test fails; bread doesn't oven spring.

Fix — switch to bread flour (12–14% protein); add more sets of folds during bulk; try a longer autolyse.

5. Oven not hot enough

The bread needs intense initial heat to spring upward before the crust sets.

Signs — pale, dull crust; minimal oven spring; spreading rather than rising in the oven.

Fix — preheat the Dutch oven 45 minutes at 500°F. Use an oven thermometer to verify.

6. Banneton too large

The dough fills horizontally instead of building vertically during the final proof.

Signs — dough comes out flat from the banneton; banneton is more than ¾ full but dough hasn't risen.

Fix — match the basket to the dough. Roughly: 9-inch round for 1kg dough. If your banneton is too big, do a final proof on a parchment-lined sheet pan with a bowl over the dough.

Diagnostic flow

1. Did the dough spread when turned out of the banneton? → Over-fermentation or under-shaping.
2. Was the dough sticky throughout? → Hydration or gluten.
3. Did the loaf spring at all in the oven? → If no, oven temperature.
4. Is the banneton matching the dough size? → If too large, change basket.

When all else fails

Run a control bake. Use a known-good recipe (try the ones from this site), exact measurements, careful timing. If the control bake works, your normal recipe has a problem. If the control fails, your starter or environment is the issue.

Salvaging flat bread

Even a flat loaf is edible. Slice for sandwiches, croutons, or French toast. Then bake again with one variable adjusted.

Most common fix

For 80% of home baker flat-loaf cases, the answer is: stop bulk fermentation 30–60 minutes earlier than you've been. Try it.