Bakeryss · Sourdough guides
Why Is My Sourdough Gummy?
A gummy crumb usually means the inside of the loaf was still wet — or still warm — when you judged it, or that something stopped the dough from setting as it should. The most common explanations are under-fermentation, cutting before the loaf had fully cooled, and not baking long enough or hot enough for the size of the loaf.
"Gummy means underproofed" is one story, not the whole story. Believing it too quickly can send you changing the wrong thing on the next bake. This article walks through the likely categories and how to tell them apart from what you can actually observe.
Start with when the loaf was cut
A warm loaf is not finished bread. The crumb keeps setting as it cools, and steam is still moving through it. Cut too early and the inside can look wet, tacky or doughy even when the bake itself was fine.
Before you blame the recipe, let the loaf cool completely and look at the crumb again. If it tightens up as it cools, the problem was partly timing, and it may not appear at all next time.
Fermentation state
If the crumb is dense and tight — especially with a few larger holes trapped near the top — the dough may not have fermented enough before it was baked. Under-fermented dough has not built the gas and the structure that give a loaf an open, even crumb.
The opposite can also look wrong. Dough left to ferment too long loses strength, can spread rather than spring, and may bake into a crumb that is dense and gummy toward the base even though it was given plenty of time.
Fermentation state is only one of several possible causes of a gummy crumb.
The bake itself
A gummy crumb can simply mean the loaf did not bake long enough, or hot enough, for its size. Large loaves, very wet doughs and a crowded oven all take longer to set in the middle than a small, drier loaf.
Steam and trapped moisture are part of a good bake, but if the crust colours well before the centre is set, the middle can stay wet. A loaf that is gummy in the very centre, with an otherwise sound crumb, points more toward the bake than the fermentation.
Before you assume it was underproofed
A gummy crumb invites a quick conclusion, but the quickest conclusion is often the wrong one. Work through these checks in order before you decide fermentation was the problem:
- When did you cut? A warm loaf can look wet and tacky even when the bake was sound — let it cool completely and look again.
- How does the crumb look from top to bottom? A few larger holes near the top with a tight base leans toward under-fermentation; density spread evenly leans toward the bake or the flour.
- How much did the dough rise, and how did it feel? Strength and rise together are more informative than either alone.
- How long did it ferment, and at what temperature? Compare with your own past bakes, not with someone else's timeline.
- What is the hydration, and which flour? High hydration and whole-grain or freshly milled flour both push the crumb toward moist and close.
Hydration and flour
Very wet doughs and flours that absorb less water — or carry more whole grain — tend to produce a moister, closer crumb. That is a style, not necessarily a fault, but it can read as gummy if you expected something airier.
Freshly milled or high-extraction flour can also make a dough behave wetter than its hydration number suggests. In that case the crumb is telling you about the flour, not about a mistake.
Starter and fermentation performance
A starter that is not at its most active, or a dough that has been kept cool, can slow fermentation enough that the dough looks ready when it is not. This often shows up in the crumb rather than in the schedule, which is why two bakes that took the same time can still differ.
Read the evidence together
Gumminess is a symptom, and several different situations produce it. The useful move is to combine what you can observe rather than trusting any single one:
Recording a few details for this bake — hydration, fermentation time and temperature, when you cut, and how the crumb looked from top to bottom — turns the next loaf into a comparison instead of a fresh guess.
- How much the dough rose, and whether the loaf sprang in the oven.
- How the dough felt — strong and springy, or slack and spreading.
- How long it fermented, and at what temperature.
- How the crumb looks from top to bottom.
- When you cut the loaf, and whether the crumb changed as it cooled.
Why "gummy equals underproofed" is too simple
Under-proofing is a real cause, and sometimes it is the right answer. But it is only one of several, and the visible symptoms overlap. Dough that was under-fermented and dough that was over-fermented can both produce a dense, disappointing crumb for different reasons.
If you assume under-proofing and simply add more time on the next bake, you may fix one loaf and overshoot the next. Comparing several signals points you at the direction that is actually more likely.