You shaped a beautiful loaf, scored it perfectly, and loaded it into a hot oven with high hopes. But 30 minutes later, your sourdough sits there—flat, dense, and stubbornly refusing to spring upward. Poor oven spring is one of the most frustrating problems in sourdough baking, but it's also one of the most solvable once you understand what's going wrong.
Oven spring—the dramatic rise that happens in the first 10-15 minutes of baking—is what transforms your dough into an airy, open-crumbed loaf with a beautiful ear. When it doesn't happen, you're left with a dense brick that doesn't match the effort you put in. Let's diagnose why your sourdough isn't rising in the oven and exactly how to fix it.
What Is Oven Spring and Why Does It Matter?
Oven spring is the rapid expansion of dough during the first phase of baking. When your shaped loaf hits the hot oven, several things happen simultaneously: gases inside the dough (primarily carbon dioxide and ethanol vapor) expand rapidly with heat, water converts to steam and pushes outward, and the yeast makes a final burst of fermentation before the heat kills it around 60°C (140°F).
This expansion continues until the crust sets and the gluten structure solidifies, usually around 10-15 minutes into the bake. Good oven spring can increase your loaf's volume by 20-30% or more. Without it, you get a flat, dense loaf that doesn't showcase the open crumb you worked so hard to develop during fermentation.
The 6 Most Common Reasons for Poor Oven Spring
1. Your Dough Is Overfermented
This is the number one culprit. Overfermented dough has exhausted its food supply and lost its structural integrity. The gluten network has begun to break down, and the yeast has produced so much gas during bulk fermentation that there's little left for oven spring.
What to look for: Dough that spreads outward instead of holding its shape after shaping, a very slack texture, large irregular holes, or a strong alcohol or vinegar smell. When you score the loaf, it may deflate slightly instead of holding tension.
The fix: Reduce your bulk fermentation time. If you're currently bulk fermenting for 6 hours at room temperature (21-24°C/70-75°F), try 4-5 hours instead. Watch for a 30-50% volume increase rather than doubling, and look for a domed top with visible small bubbles under the surface. The poke test should show dough that springs back slowly but leaves a slight indentation—not dough that stays completely collapsed.
2. Your Dough Is Underfermented
The opposite problem: dough that hasn't fermented enough won't have developed sufficient gas bubbles or gluten strength. Underfermented dough is tight, hard to shape, and springs back immediately when poked. In the oven, it doesn't have the structure or gas production to rise properly.
What to look for: Dense, tight dough that's difficult to stretch during shaping. When scored, it barely opens. The baked loaf has a very tight, uniform crumb with few holes. The poke test shows dough that springs back immediately and completely.
The fix: Extend bulk fermentation. Use visual cues—look for 50-75% volume increase, a soft jiggly texture, visible bubbles throughout (not just on top), and a domed surface. Temperature matters enormously here: if your kitchen is 18°C (65°F), you might need 8-10 hours instead of 4-5. Consider using a proofing box or finding a warmer spot (like inside an oven with the light on) to speed fermentation.
3. You're Not Creating Enough Steam
Steam is critical for oven spring. It keeps the crust soft and pliable during the first 15-20 minutes of baking, allowing the loaf to expand freely. Without steam, the crust sets too quickly, essentially creating a hard shell that prevents the bread from rising.
What to look for: A thick, hard crust that forms very early in the bake. The loaf may have good color but minimal rise. Your score marks barely open up.
The fix: If using a Dutch oven, preheat it for at least 45 minutes at 260°C (500°F). The heavy lid traps the moisture released by the dough, creating a steamy environment. If you're baking on a stone or steel, you need to create steam manually—place a metal pan on the oven floor during preheat, then add 1 cup of boiling water (or ice cubes) right when you load the bread. Some bakers spray the oven walls with water, but this is less effective than a steam pan.
4. Your Oven Temperature Is Too Low
An oven that's not hot enough won't trigger the rapid expansion needed for oven spring. The dough gradually warms instead of getting a sudden heat shock, giving the yeast time to die off before maximum gas expansion occurs.
What to look for: Pale crust color even after the recommended baking time, very gradual rise instead of dramatic spring, and an overall underwhelming result despite proper fermentation.
The fix: Use an oven thermometer—many home ovens run 10-25°C (20-45°F) cooler than the dial indicates. Preheat to 260°C (500°F) for at least 45 minutes (an hour is better). When you load the bread, reduce to 230-235°C (450-455°F) for the covered portion if using a Dutch oven. That initial blast of heat is crucial for triggering oven spring.
5. Your Shaping Created a Weak Structure
Even perfectly fermented dough won't rise well if you haven't created adequate surface tension during shaping. The "skin" of the dough needs to be tight enough to contain expanding gases and direct them upward rather than allowing the loaf to spread sideways.
What to look for: Loaves that spread wide and flat rather than rising tall. The dough may feel slack and loose during shaping, like it's not holding together.
The fix: Work on your shaping technique. During pre-shape, create a tight ball by pulling the dough toward you on an unfloured surface—the slight stick creates tension. Let it rest 20-30 minutes, then do your final shape with deliberate tension. For a batard, create a tight cylinder by folding and rolling with firm pressure. For a boule, stitch the bottom or use the drag-and-turn method. The surface should feel taut like a drum, not loose and slack.
6. Your Scoring Technique Is Limiting Expansion
The score (or slash) you make before baking isn't just decorative—it's a deliberate weak point that controls where the bread expands. Poor scoring can actually prevent oven spring by not giving the gases anywhere to escape, or by releasing all the tension at once.
What to look for: Bread that bursts open randomly along the sides rather than opening at your score. Or scores that barely open at all, creating a flat appearance.
The fix: Use a very sharp blade (a lame with a fresh razor blade works best). Score at a 30-45 degree angle, not straight down—this creates an ear that lifts as the loaf rises. Score decisively in one smooth motion about 0.5-1 cm (¼-½ inch) deep. Don't saw back and forth. For a batard, one long score down the length works well. Score immediately before loading into the oven—don't let scored dough sit, as it will begin to deflate.
How to Test and Troubleshoot Your Oven Spring
The best way to identify your specific issue is to keep a baking journal. For each loaf, note: bulk fermentation time and temperature, poke test results, final proof time and method (counter or refrigerator), oven temperature (verified with thermometer), steam method, and the result.
After 3-4 loaves, patterns will emerge. If you're consistently getting flat loaves that spread wide with a strong sour flavor, you're overfermented. If you're getting tight, dense loaves with barely any opening at the score, you're likely underfermented or not creating enough steam.
Try the half-and-half test: Make your dough as usual, but divide it after bulk fermentation. Proof one portion for your normal time, and the other for 30-45 minutes less. Bake them both and compare. This helps you dial in whether fermentation timing is your issue.
The Ideal Conditions for Maximum Oven Spring
When everything comes together, here's what you should see: Dough that's fermented to 50-75% volume increase, soft and jiggly but still holding shape. A poke test that leaves a slow-filling indentation. Surface tension from shaping that makes the loaf feel taut. An oven preheated to 260°C (500°F) for at least 45 minutes. A Dutch oven or effective steam setup. A decisive score at 30-45 degrees, 0.5-1 cm (¼-½ inch) deep.
Load your bread, and within 2-3 minutes you should see the score beginning to open. By 10 minutes, dramatic expansion should be visible. By 15 minutes, the loaf should have reached its maximum volume, and you'll see the crust just beginning to color.
What to Do Right Now
If your last loaf had poor oven spring, don't change everything at once—you won't know what fixed it. Pick the most likely culprit based on your symptoms and adjust one variable.
If you suspect overfermentation: Reduce bulk fermentation by 1-2 hours and watch for earlier visual cues.
If you suspect underfermentation: Extend bulk fermentation by 1-2 hours or increase your dough temperature.
If you suspect temperature or steam issues: Invest in an oven thermometer and ensure your Dutch oven preheats for a full hour.
If you suspect shaping: Watch video tutorials on creating surface tension and practice with each loaf.
Oven spring is the moment where all your work pays off—or doesn't. But unlike some baking mysteries, this one follows clear cause-and-effect. Dial in your fermentation, create steam, get your oven screaming hot, and shape with intention. Your next loaf will rise.