Sourdough Bread Didn’t Rise? 5 Reasons and What to Change

Alright, let me guess. You spent the better part of a day mixing, folding, shaping, and patiently waiting for your sourdough to do its thing. You slid that beautiful boule into a screaming-hot Dutch oven with all the hope in the world. And when you pulled off the lid… pancake. A dense, flat, slightly sad disc of bread that looks more like a frisbee than the gorgeous, ear-popping loaf you saw on Instagram.

Friend, I have been there. More times than I care to admit. My first six months of sourdough baking produced enough flat loaves to tile my kitchen floor. But every single flat loaf taught me something, and now I can almost always diagnose the problem before I even cut into it. So let me walk you through the five biggest reasons your sourdough bread didn’t rise and, more importantly, what to change next time.

Reason 1: Your Starter Wasn’t Ready

This is the number one cause of flat loaves, especially for newer bakers. Your sourdough starter is a living colony of wild yeast and bacteria, and it needs to be at peak activity when you mix your dough. If your starter is sluggish, underfed, or past its peak, it simply won’t have the strength to leaven your bread properly.

A ready starter should pass the float test: drop a small spoonful into a glass of water, and it should float. But honestly, I rely more on visual cues. A peak starter has roughly doubled in volume from its last feeding, has a domed top (not collapsed or concave), smells pleasantly tangy rather than sharp or like nail polish remover, and is full of bubbles throughout. If you scoop a bit with a spoon, it should look airy and almost mousse-like inside.

If your starter isn’t doubling reliably, it needs more consistent feeding before you use it in a bake. Feed it twice a day at a 1:5:5 ratio (starter, flour, water by weight) for three to five days and keep it at around 75-78°F. Once it’s consistently doubling within 4-6 hours of feeding, it’s strong enough for bread. Our guide to creating a sourdough starter from scratch covers this process in detail, and our starter rescue guide can help if yours is struggling.

Reason 2: Bulk Fermentation Was Too Short (or Too Cold)

Bulk fermentation is when the magic happens. This is the long rest after you mix your dough, when the yeast produces carbon dioxide and the gluten network traps those bubbles to create structure. If you cut this phase short, you get an under-fermented dough that hasn’t built up enough gas to rise properly in the oven.

The tricky thing about bulk fermentation is that it’s driven by time and temperature together. A dough fermenting at 80°F might be ready in 4 hours. The exact same dough at 68°F might need 8 hours or more. If your kitchen is cold and you’re following a recipe that assumes a warm kitchen, your dough will be massively under-fermented when you move to shaping.

I keep a cheap ambient thermometer next to my dough during bulk fermentation. If my kitchen drops below 72°F, I know I need to extend the time significantly. Some bakers use their oven with just the light on as a makeshift proofing box, which keeps things at a steady 78-80°F. A detailed breakdown of the entire process is in our bulk fermentation guide.

Signs You Under-Fermented

After baking, cut your loaf in half. If the crumb is dense at the bottom with a slightly more open crumb on top, that’s classic under-fermentation. You might also see a gummy or wet-looking texture near the base, even though the bread is fully baked through. The flavor will likely be more wheaty and less tangy than expected, because the bacteria haven’t had enough time to produce lactic and acetic acids.

Another telltale sign is a very tight, closed crumb with no discernible holes throughout. While not everyone is chasing a wildly open crumb, a properly fermented loaf should have at least some visible air pockets distributed throughout. If it looks like cake rather than bread, fermentation was probably cut short.

Reason 3: You Over-Proofed the Dough

This is the flip side of under-fermentation, and it’s equally devastating. Over-proofed dough has fermented for too long. The yeast has consumed nearly all the available sugars, the gluten network has weakened from prolonged acid production, and there’s no more oomph left for oven spring. When you score an over-proofed loaf, the dough deflates rather than holding its shape. The scoring lines spread apart rather than opening up into a crisp ear.

Over-proofing often happens during the cold retard (overnight refrigerator proof) if your fridge runs warm or if the dough was already quite gassy when it went in. It can also happen if you leave your shaped dough on the counter for too long before baking, especially in a warm kitchen.

The poke test is your friend here. Press your finger about half an inch into the shaped dough. If it springs back quickly and completely, it’s under-proofed. If it springs back slowly and leaves a slight indent, it’s perfectly proofed. If the indent stays and doesn’t spring back at all, you’ve gone too far. An over-proofed dough feels almost marshmallow-like, extremely soft and pillowy with very little resistance.

Reason 4: Weak Gluten Development

Gluten is the structural framework that holds your bread together and traps the gas produced during fermentation. Without adequate gluten development, the dough can’t hold its shape or retain those precious bubbles. The result is a flat, spread-out loaf that bakes into a dense brick.

Gluten develops through a combination of hydration, time, and mechanical action (mixing or folding). If you’re doing a low-effort, minimal-fold recipe, you might not be building enough structure, especially if you’re using a lower-protein flour. Bread flour (12-14% protein) develops a much stronger gluten network than all-purpose flour (10-12% protein). If your recipe calls for bread flour and you’re using all-purpose, you’ll need to compensate with more folds and possibly lower hydration.

Here’s what proper gluten development looks like: after your stretch-and-fold series, the dough should feel noticeably smoother, more elastic, and more cohesive. If you pull off a small piece and gently stretch it between your fingers, you should be able to stretch it thin enough to see light through it without it tearing. This is called the windowpane test, and it’s the gold standard for checking gluten development.

Building Stronger Gluten

If your loaves consistently come out flat and spread-y, try adding more folds during bulk fermentation. Instead of three sets of stretch-and-folds in the first hour, do four or five sets spaced 20-30 minutes apart. You can also try adding a brief initial mix, working the dough for 5-10 minutes by hand using the slap-and-fold technique before you start bulk fermentation. This gives you a head start on gluten development that the stretch-and-folds can then build upon.

Using bread flour with higher protein content makes a genuine difference. I switched from grocery store all-purpose to King Arthur bread flour early in my sourdough journey, and the improvement was immediately noticeable. The dough held its shape better during shaping, the loaf had more oven spring, and the crumb was more open. If you want to incorporate whole grains, our whole wheat sourdough guide shows how to do it without sacrificing structure.

Reason 5: Shaping Issues

You can nail the fermentation and gluten development, but if your shaping technique is weak, the loaf will still come out flat. Shaping serves two critical purposes: it creates surface tension on the outside of the dough (which helps the loaf hold its shape and rise upward rather than outward), and it organizes the gas bubbles into a more even distribution.

A well-shaped boule or batard should feel taut on the surface, almost like a filled water balloon. When you place it in the banneton, it should hold its round or oval shape rather than spreading out and filling the basket. If your dough relaxes immediately after shaping and puddles out like a jellyfish, you either need tighter shaping or your dough needs a rest (called a bench rest) before shaping to let the gluten relax and then re-tighten.

Common Shaping Mistakes

The most common mistake I see is being too gentle during shaping. You need to apply firm, deliberate tension without degassing the dough completely. Think of it like tucking a fitted sheet around a mattress, you’re pulling and tucking to create a smooth, taut surface. Another frequent mistake is using too much flour during shaping. A light dusting is fine, but too much flour prevents the dough from gripping the work surface, which makes it impossible to build tension. The dough just slides around instead of grabbing and tightening.

Some bakers also struggle because they shape on a surface that’s either too sticky (dough sticks everywhere and tears) or too smooth and floured (no grip at all). A lightly floured wooden cutting board or a slightly tacky countertop works best. You want just enough friction that the dough catches and tightens as you drag it toward you.

Bonus: Oven Spring Killers

Even if your fermentation and shaping are perfect, a few oven-related issues can sabotage your rise. First, make sure your oven is fully preheated. I preheat my Dutch oven at 500°F for a full hour. Yes, an hour. Oven thermometers lie, and a truly hot baking vessel is essential for maximum oven spring. Once the bread goes in, I drop the temperature to 450°F for the covered bake.

Second, steam matters. If you’re baking without a Dutch oven, you need steam in the oven during the first 15-20 minutes of baking. Steam keeps the crust soft and pliable so the loaf can expand before the crust sets. Without steam, the crust hardens almost immediately and locks the bread at its current size. A Dutch oven traps the steam naturally from the moisture in the dough itself. For more on getting that perfect crispy exterior, our crusty crust guide covers all the details.

Third, scoring depth matters. Score your loaf about a quarter to half inch deep, at a slight angle (about 30 degrees from the surface). Too shallow and the score won’t open up. Too deep and you deflate the dough. A sharp lame or razor blade makes all the difference here since a dull blade drags and tears the dough rather than slicing cleanly.

Putting It All Together: A Diagnostic Checklist

Next time you pull a flat loaf from the oven, work through this checklist before your next bake:

Was my starter at peak activity? Check that it was doubled and domed, not collapsed. Feed it more consistently if needed and make sure you’re using it within the right window. If your starter has been neglected, rescue it first before attempting another bake.

Did I ferment long enough? Check for 50-75% volume increase. Use a thermometer to know your actual kitchen temperature and adjust timing accordingly. Our bulk fermentation guide has temperature-to-time charts that can help.

Did I over-proof? Use the poke test before baking. If the indent doesn’t spring back at all, you’ve gone too far.

Is my gluten strong enough? Do the windowpane test. If the dough tears immediately when stretched thin, add more folds or switch to bread flour.

Is my shaping tight enough? The dough should feel taut like a drum, not slack and floppy. Don’t skip the pre-shape.

Is my oven hot enough? Preheat longer than you think. Use an oven thermometer. Make sure you have steam.

The Bottom Line

A flat sourdough loaf is almost always caused by one of these five things: a weak or past-peak starter, under-fermentation during bulk, over-proofing, insufficient gluten development, or poor shaping technique. Sometimes it’s a combination of two or more. The good news is that every single one of these problems has a clear, specific fix.

Start by addressing whatever you think is most likely the culprit in your specific situation. Make one change at a time so you can see what’s actually helping. Keep notes on every bake (time, temperature, how the dough looked and felt at each stage) and within a few loaves, you’ll start to develop the instinct for what properly fermented, well-developed dough looks and feels like. That instinct is what separates a frustrated beginner from a confident baker, and it only comes from paying attention and putting in the reps.

Now go feed your starter. Your next loaf is going to be better.