You slice into your sourdough loaf expecting beautiful, even holes—but instead you find a few massive caverns surrounded by dense, tight crumb. It's frustrating because you almost got it right. Your dough rose well, it has oven spring, but the crumb structure is wildly uneven. This inconsistent crumb—often called "flying crust" or "cathedral crumb"—is one of the most common problems intermediate bakers face, and it's actually a sign that you're closer to success than you think.
An uneven crumb with large irregular holes and dense areas happens when gas distribution during fermentation and shaping is inconsistent. The large holes form where gas pockets weren't properly incorporated, while the dense patches show where gluten structure collapsed or where dough wasn't adequately aerated. The good news? This is entirely fixable with adjustments to your technique.
Why Your Sourdough Crumb Is Uneven
Several factors create this problematic crumb structure, and they often work together:
Insufficient or Aggressive Shaping
This is the most common culprit. When you shape too gently, you don't redistribute the large gas pockets that formed during bulk fermentation—they stay put and become those massive holes. When you shape too aggressively, you degas the dough completely, creating dense areas while a few stubborn pockets remain as large holes.
The goal during shaping is to redistribute gas evenly throughout the dough, not to eliminate it entirely. You want to create consistent, moderate tension that encourages uniform small-to-medium holes rather than a few giant ones.
Poor Gluten Development
Weak gluten structure can't hold gas bubbles evenly. Instead of a network of consistent bubbles, you get a few large pockets where gas migrated and collected, surrounded by collapsed, dense dough that couldn't maintain structure.
If you're not building sufficient strength during mixing and folding, or if you're using lower-protein flour without adjusting your technique, your dough won't have the structural integrity to create even holes.
Uneven Fermentation Temperature
When different parts of your dough ferment at different rates—like when the edges of your bowl are warmer than the center, or when one side faces a heat source—you get inconsistent gas production. Warmer areas produce more gas and create larger holes, while cooler spots remain dense.
This is especially common if you proof near a radiator, in direct sunlight, or in a bowl that's not regularly turned.
Overproofing (But Not Quite Everywhere)
Dough that's pushed slightly too far often shows this pattern. The gluten structure begins to weaken and can't hold smaller bubbles—they merge into large cavities. Meanwhile, areas where gluten has collapsed entirely become dense and gummy.
If you're seeing very large holes near the top of your loaf with dense crumb at the bottom, overproofing combined with poor shaping is likely the cause.
Inconsistent Folding Technique
During bulk fermentation, coil folds or stretch-and-folds should distribute gas and strengthen gluten throughout the entire dough. If you're only folding from certain directions, or if parts of your dough aren't getting worked, you'll create uneven structure.
How to Achieve Even, Consistent Crumb
Perfect Your Shaping Technique
Pre-shape with intention. After bulk fermentation, turn your dough out and pre-shape it into a loose round. This first shaping should gently redistribute the largest gas pockets without degassing entirely. Let it rest for 20-30 minutes.
Final shape with consistent tension. During final shaping, focus on creating even tension across the entire dough surface. For a boule, use the same pressure as you fold and tighten. For a batard, ensure your rolling motion applies consistent pressure from end to end.
Practice the "fold and tighten" method: Fold the dough from different angles (top, sides, bottom), pulling gently to create surface tension each time. You should feel resistance, but the dough shouldn't tear. Aim for 4-6 folds that incorporate the entire dough mass.
Build Better Gluten Structure
Increase your folding frequency early in bulk. Perform coil folds or stretch-and-folds every 30 minutes for the first 2 hours of bulk fermentation. This builds a strong gluten network before significant gas production begins.
Use the windowpane test after mixing. After your initial mixing or autolyse, test whether you can stretch a small piece of dough thin enough to see light through it without tearing. If not, perform additional folds or slap-and-folds until you can.
Consider a slightly longer autolyse. Letting flour and water rest for 30-60 minutes before adding starter and salt gives gluten time to develop naturally, creating better structure with less work.
Control Fermentation Temperature
Aim for 21-24°C (70-75°F) ambient temperature. This range promotes even, controlled fermentation. Use a thermometer to monitor your proofing environment, not just your dough temperature.
Rotate your container during bulk fermentation. Every time you perform a fold, turn the bowl 180 degrees. This ensures all sides experience the same environmental conditions.
Use a proofing box or insulated cooler. If your kitchen temperature fluctuates significantly, create a more stable environment. A proofing box, turned-off oven with the light on, or cooler with a jar of warm water can maintain steady temperature.
Watch Your Fermentation Timing
End bulk fermentation at 50-75% volume increase, not double. Dough that doubles often develops those very large, irregular holes. For a more even crumb, catch it earlier when the gluten structure is still robust.
Look for a dome, not a plateau. Your dough should have a gently domed surface at the end of bulk. If it's flattened or starting to look wrinkled on top, you've gone too far.
Use the poke test correctly. When you gently poke your dough, it should spring back slowly but not completely—leaving a slight indentation. If it springs back immediately, continue fermenting. If it doesn't spring back at all, you may be overproofed.
Improve Your Folding Consistency
Work the entire dough mass. Whether you're doing coil folds or stretch-and-folds, make sure every part of the dough gets incorporated. For coil folds, lift from the center and let the sides fold under. For stretch-and-folds, work all four sides.
Don't skip folds. Especially in the first half of bulk fermentation, each fold distributes gas and builds strength. Missing even one fold can create uneven structure.
Be gentle in the second half of bulk. After 2-3 hours of bulk fermentation, switch to gentler coil folds rather than aggressive stretch-and-folds. You're maintaining structure now, not building it.
The Role of Hydration in Crumb Evenness
Higher hydration doughs (above 75%) are more prone to uneven crumb because the looser dough structure allows gas to migrate more easily into large pockets. If you're consistently struggling with this issue, try reducing hydration by 5%—from 75% to 70%, for example.
Lower hydration gives you more control during shaping and creates a slightly tighter crumb structure that's more forgiving. Once you master even crumb at 70%, you can gradually increase hydration while applying the same techniques.
What Even Crumb Should Look Like
An even, open crumb has holes that are relatively consistent in size—ranging from small to medium, with a few larger ones scattered throughout. There shouldn't be dense, tight areas that look like sandwich bread next to caverns large enough to lose butter in.
The holes should be distributed throughout the entire cross-section, from top to bottom, edge to center. The crumb should feel light and airy when you press it, springing back gently. When you tear (not cut) a piece, you should see thin, translucent gluten strands connecting the holes.
Troubleshooting Specific Patterns
Large holes at the top, dense at the bottom: This usually indicates overproofing combined with insufficient shaping tension. The bottom of your loaf is compressed by the weight of the dough during final proof. End bulk fermentation earlier and increase tension during final shaping.
Dense ring around the edges, open in the center: This suggests uneven shaping pressure. You're creating too much tension on the outside while leaving the center loose. Focus on distributing tension evenly across the entire surface during shaping.
Random massive holes surrounded by okay crumb: You're not redistributing gas during shaping. Focus on your pre-shape—gently deflate the largest pockets before final shaping. Also ensure you're folding from multiple directions.
Consistently tight crumb with just 2-3 giant holes: You're likely degassing too much during shaping (removing all the small bubbles) while missing a few large pockets. Lighten your touch and work more systematically to incorporate the whole dough.
The Practice Schedule: Developing Feel Over Four Bakes
Bake 1: Focus on fermentation timing. End bulk fermentation at 50% volume increase (not your usual 75-100%). Note how the crumb differs.
Bake 2: Focus on folding. Perform folds every 30 minutes for the first 2 hours, working the entire dough mass each time. Compare the crumb structure to your previous bake.
Bake 3: Focus on shaping. Pay specific attention to pre-shaping and redistributing gas. Use consistent, moderate pressure during final shape. This is where you'll likely see the biggest improvement.
Bake 4: Combine all adjustments. Proper folding, correct fermentation endpoint, and intentional shaping. Your crumb should now be noticeably more even.
The Bottom Line
Uneven crumb with large holes and dense patches isn't a sign of failure—it's a sign you're developing fermentation and oven spring, but need to refine your technique. The fix lies primarily in how you shape your dough and how evenly you build and maintain gluten structure throughout fermentation.
Most bakers see dramatic improvement within 2-3 loaves once they focus on consistent shaping pressure and ending bulk fermentation earlier. The goal isn't perfection—it's consistent, even holes that create that satisfying, airy texture throughout your entire slice.