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Free Guide · Troubleshooting

Sourdough bread flat or not rising? Causes and fixes

A loaf that spreads out instead of up is frustrating, but the cause is usually one of four things. Here is how to tell which one it was.

By Maurice Elsäßer · Last updated 26 October 2026

The usual causes

  1. Over-fermented dough. This is the most common reason. The gluten network is stretched out and cannot hold the gas. The dough often feels slack and sticky and smells sharp or boozy.
  2. Not enough tension when shaping. A loose shape has nothing to hold it up, so it spreads sideways in the oven.
  3. A weak or tired starter. Little lifting power from the start means the dough never builds enough strength.
  4. Too much water for the flour. Very wet dough spreads easily, especially if shaping is not firm.
  5. The oven was not hot enough, or there was no steam. Steam and strong heat at the start let the loaf rise before the crust sets.
Tall round sourdough loaf with strong oven spring and open scoring
A loaf that kept its height and opened in the oven. Our own Bauernkruste.
If you are unsure, bake earlier next time. Slightly under-fermented dough still rises. Over-fermented dough cannot recover.

How to tell which one it was

  • Slack, sticky, sour smell: over-fermented. Shorten the rise next time.
  • Dough felt fine but spread right after shaping: shaping tension. Shape more firmly and keep a taut surface.
  • Dough barely grew at all: weak starter or a room that was too cool.
  • Dough was good, but the loaf did not jump in the oven: check preheating and steam.

The Starter Kit includes the poke test for dough readiness, shaping guidance and a troubleshooting table (Module 5) that points every flat loaf to its cause.

Get the Starter Kit — €16

Frequently asked questions

Why does my sourdough spread flat instead of rising?

Usually because the dough was over-fermented or shaped without enough tension. A weak starter or very wet dough can add to it.

Can I save dough that has over-fermented?

Shape it and bake it right away. It may come out flatter, but it will still make good bread. Next time, shorten the rise.

Does a flat loaf mean my starter is dead?

Not necessarily. Most flat loaves come from timing or shaping. Check the starter with the dome test before you decide.

Do I need a Dutch oven to get a tall loaf?

No, but you need strong heat and steam at the start of the bake. A Dutch oven provides both. Other setups can work if they do the same.

Want to read the dough better? See how to tell when bulk fermentation is done.

The guides teach the basics. The kits take you all the way.

Seven step-by-step modules from first mix to first loaf. The Starter Kit is where the craft begins.

Get the Starter Kit — €16