Why Is My Sourdough Flat? Troubleshooting Guide

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A flat sourdough loaf is disappointing but extremely common, especially for newer bakers. The good news is that flat loaves almost always trace back to a few identifiable causes, all of which have straightforward solutions.

Weak or Inactive Starter

The most common cause of flat bread is an underactive starter. If your starter is not doubling within 6-8 hours of feeding, it does not have the strength to leaven your dough properly. Feed it twice daily for a few days to boost activity.

The float test, dropping a spoonful of starter in water, is not always reliable. A better indicator is consistent doubling after feeding and a pleasantly sour aroma. Use your starter at its peak rise for the strongest leavening power.

Troubleshooting flat sourdough loaves — practical guide overview — Troubleshooting flat sourdough loaves

💡 Good to know: Temperature dramatically affects fermentation speed. A 10-degree difference can cut or double your bulk fermentation time. Use a thermometer to track your dough temperature and adjust timelines accordingly.

Over-Fermentation

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Over-proofed dough has exhausted its food supply. The gluten structure weakens, and the dough cannot hold its shape during baking. It feels overly soft, jiggly, and may have large surface bubbles. It spreads flat in the oven.

Reduce bulk fermentation time or lower the ambient temperature. A 75-80% rise during bulk is usually better than waiting for a full double. The poke test helps, if the dough does not spring back at all when pressed, it has gone too far.

Troubleshooting flat sourdough loaves — step-by-step visual example — Troubleshooting flat sourdough loaves

✅ Tip: Take a photo of your dough at the start and end of bulk fermentation from the same angle. Comparing these images makes it much easier to judge the actual rise than relying on memory.

Under-Developed Gluten

Without adequate gluten development, dough cannot trap the gas produced during fermentation. It rises during bulk but collapses during shaping and baking. Ensure you are performing enough stretch and folds, at least 3-4 sets during bulk.

Low-protein flour also contributes to weak structure. Use bread flour with at least 11.5% protein for sourdough. All-purpose flour works but may need additional gluten development through more folds or a longer autolyse.

Shaping Problems

Even well-fermented dough falls flat without proper shaping. Surface tension is what holds the loaf upright in the oven. Practice creating a tight, smooth outer skin during your final shape by pulling the dough toward you on an unfloured surface.

If your dough is too wet to shape, use less water next time or improve your shaping technique with wet hands. A bench knife is essential for handling sticky dough during pre-shaping and final shaping.

Troubleshooting flat sourdough loaves — helpful reference illustration — Troubleshooting flat sourdough loaves

💡 Good to know: Consistency in your process matters more than any single technique. Track your results, make notes, and refine your approach one variable at a time.

What We Learned

The techniques and knowledge shared here build the foundation for consistent, rewarding results. Whether you are just starting out or refining your craft, focusing on fundamentals always pays dividends.

Start with what interests you most, practice deliberately, and do not be afraid to experiment. Every batch teaches you something new, and the journey of improvement is what makes this pursuit so engaging.