Why Does My Sourdough Bread Collapse And How To Fix The Crumb Structure

Sourdough bread is a marvel of natural fermentation—tangy, complex, and deeply satisfying when done right. But even experienced bakers can be frustrated by loaves that rise beautifully in the oven only to sink into a dense, flat mess. A collapsed loaf or poor crumb structure isn’t just disappointing—it can signal deeper issues in your process. Understanding the root causes and applying targeted fixes transforms inconsistent results into reliable, bakery-quality bread.

The Science Behind Sourdough Collapse

Sourdough relies on a delicate balance between gluten development, gas production from wild yeast and bacteria, and structural integrity during proofing and baking. When any part of this system fails, the loaf may collapse. The most common moment for collapse is during or immediately after baking, but it can also happen during bulk fermentation or final proof.

Gluten forms the elastic network that traps carbon dioxide produced by fermentation. If the gluten matrix is weak or over-fermented, it cannot support the expanding gases. Similarly, if the dough is under-proofed, it lacks sufficient gas; if over-proofed, the structure becomes too fragile. Both extremes lead to structural failure.

Temperature plays a critical role. Cold dough expands slowly and retains strength. Warm environments accelerate fermentation, increasing the risk of over-proofing. Even minor variations in room temperature or hydration can shift the entire timeline.

“Sourdough isn’t about perfection—it’s about understanding cause and effect. Every collapse teaches you something about fermentation timing and dough strength.” — Daniel Leader, author of *Local Breads* and founder of Bread Alone Bakery

Common Causes of Sourdough Collapse

Several interrelated factors contribute to collapsed loaves. Identifying which one (or combination) applies to your bake is key to fixing the problem.

1. Over-Proofing

This is the leading cause of collapse. When dough proofs too long, the yeast exhausts available sugars, producing excess acid and weakening the gluten. The structure becomes fragile and unable to hold its shape during baking.

Signs of over-proofing include:

• Dough doesn’t spring back when poked
• Surface appears bubbly or deflated
• Loaf spreads outward instead of rising upward

2. Underdeveloped Gluten

If gluten hasn’t been sufficiently strengthened through mixing, folding, or autolyse, the dough lacks the tensile strength to trap gas. This leads to early collapse or poor oven spring.

Wet doughs (high hydration) are especially vulnerable because water dilutes gluten formation unless properly developed through stretch-and-folds.

3. Inconsistent Starter Activity

A weak or underripe starter won’t produce enough gas to lift the loaf. Conversely, an overripe starter produces excessive acidity, which breaks down gluten over time.

Your starter should peak 4–8 hours after feeding, doubling in volume with visible bubbles throughout. Using it too early or too late disrupts fermentation balance.

4. Poor Scoring Technique

Scoring controls where the loaf expands during oven spring. If cuts are too shallow, too deep, or improperly angled, pressure builds unpredictably, causing the loaf to burst at weak points or deflate.

Tip: Score with confidence using a sharp blade (lame or razor). Make decisive cuts at a 45-degree angle, about 1/2 inch deep.

5. Incorrect Baking Temperature or Steam Levels

Oven spring—the rapid rise during the first 15 minutes of baking—depends on proper heat and steam. Without enough initial heat, the crust sets too slowly, allowing the loaf to spread. Without steam, the surface dries out prematurely, restricting expansion.

How to Fix Crumb Structure Issues

A good crumb—open yet cohesive, with irregular holes and a tender bite—is the hallmark of well-executed sourdough. Poor crumb often stems from imbalances in hydration, fermentation, or handling.

Hydration vs. Strength

Higher hydration (75% and above) creates more open crumb but demands stronger gluten development. Beginners often increase water without adjusting technique, resulting in floppy dough and gummy centers.

To improve crumb at higher hydration:

• Perform multiple stretch-and-folds during bulk fermentation
• Extend autolyse (resting flour and water before adding starter/salt)
• Use strong bread flour with high protein content (12–13%)

Fermentation Timing

Bulk fermentation should last until the dough has increased by 50–75%, feels airy, and shows visible bubbles. It should retain some firmness when pressed. Final proof should be 75–90% complete—never fully risen.

Under-proofed loaves have tight, cake-like crumb. Over-proofed loaves collapse and develop large voids near the crust.

Baking Execution

Preheat your oven and baking vessel (Dutch oven or combo cooker) for at least 45 minutes at 450°F (230°C). Bake covered for 20–25 minutes to trap steam, then uncover and finish baking for another 20–25 minutes until deeply browned.

An internal temperature of 208–210°F (98–99°C) indicates full gelatinization of starches and proper set structure.

Troubleshooting Checklist

Use this checklist to diagnose and prevent collapse and poor crumb:

1. ✅ Is your starter peaking within 4–8 hours of feeding?
2. ✅ Did you perform adequate stretch-and-folds (3–4 sets over 2 hours)?
3. ✅ Was bulk fermentation stopped at 50–75% volume increase?
4. ✅ Was final proof timed correctly (usually 2–4 hours at room temp or overnight in fridge)?
5. ✅ Was the dough cold when scored and baked (retarding helps stability)?
6. ✅ Was the oven fully preheated with vessel inside?
7. ✅ Did you score deeply and confidently before baking?
8. ✅ Did you use steam during the first phase of baking?
9. ✅ Did the loaf reach at least 208°F internally?
10. ✅ Did you cool completely (2+ hours) before slicing?

Tip: Retard your shaped loaf in the refrigerator overnight. Cold slows fermentation, strengthens gluten, and makes scoring easier.

Real Example: From Flat Loaf to Open Crumb

Sarah, a home baker in Portland, struggled for months with dense, pancake-like loaves. Her starter was active, she followed recipes precisely, yet her bread consistently collapsed after removing the Dutch oven lid.

After reviewing her process, she realized two issues: she was letting her final proof go for 5 hours at room temperature (over-proofing), and she wasn’t performing stretch-and-folds during bulk fermentation. She also used all-purpose flour, which lacked the protein needed for high-hydration dough.

She adjusted by:

• Switching to bread flour
• Adding four sets of stretch-and-folds every 30 minutes
• Reducing final proof to 2.5 hours at room temp
• Starting to use cold retardation

Within two bakes, her loaves rose higher, held their shape, and developed an airy, even crumb. The transformation wasn’t magic—it was methodical correction.

Do’s and Don’ts for Stable Sourdough

Do’s	Don’ts
Do use a ripe, bubbly starter at peak activity	Don’t use a starter straight from the fridge without feeding
Do strengthen gluten with folds or slap-and-fold technique	Don’t skip bulk fermentation folds, especially with wet dough
Do cold-retard the shaped loaf for better control	Don’t proof at warm temperatures (>78°F) unless shortening time
Do preheat oven and vessel thoroughly	Don’t rush preheating—underheated ovens kill oven spring
Do score with a sharp blade at a 45° angle	Don’t hesitate while scoring—weak cuts don’t release pressure

Step-by-Step Guide to Prevent Collapse

Follow this sequence to build resilience into your sourdough process:

1. Feed your starter 6–8 hours before baking. Use equal parts flour, water, and starter by weight. Let it sit at room temperature until doubled and bubbly.
2. Autolyse flour and water for 30–60 minutes. This hydrates the flour and begins gluten development before adding starter and salt.
3. Mix in starter and salt, then perform 3–4 sets of stretch-and-folds over 2 hours. Wait 30 minutes between each set to allow gluten to relax and strengthen.
4. Bulk ferment until 50–75% expanded (usually 3–5 hours). Look for bubbles, jiggly texture, and slight doming.
5. Shape gently and place in a floured banneton. Avoid degassing; preserve gas pockets.
6. Final proof for 2–4 hours at room temperature or overnight in the fridge. Cold proofing reduces over-fermentation risk.
7. Preheat oven and Dutch oven to 450°F (230°C) for 45 minutes. Ensure full thermal saturation.
8. Score the loaf decisively, then transfer to hot pot. Work quickly to minimize heat loss.
9. Bake covered for 25 minutes, then uncovered for 20–25 minutes. Finish until deep golden brown.
10. Cool completely on a wire rack (minimum 2 hours). Slicing too early collapses the internal structure.

FAQ: Common Questions About Sourdough Collapse

Why does my sourdough rise in the oven and then fall?

This usually indicates over-proofing. The dough enters the oven with already weakened gluten. Initial oven spring inflates it further, but the structure can’t sustain the expansion and collapses as gases escape or moisture shifts.

Can I fix a collapsed loaf?

No—but you can learn from it. Evaluate your proofing time, starter strength, and gluten development. A collapsed loaf is still edible; toast it or use it for breadcrumbs. The next bake will improve with adjustments.

Should I always refrigerate my dough before baking?

Retarding (cold proofing) isn’t mandatory but highly recommended. It slows fermentation, enhances flavor, firms up the dough for easier scoring, and reduces collapse risk. Many bakers find it essential for consistent results.

Master Your Method, One Loaf at a Time

Sourdough baking is both art and science—a continuous dialogue between variables like time, temperature, hydration, and technique. Collapse isn’t failure; it’s feedback. Each misshapen loaf reveals where your process needs refinement.

Start by mastering one variable at a time: perfect your starter routine, then focus on fold technique, then nail proofing times. Document your bakes—note room temperature, fermentation duration, and outcomes. Patterns will emerge.

With patience and precision, you’ll move from unpredictable results to loaves that rise proudly, crackle invitingly, and slice open to reveal a crumb that’s as beautiful as it is delicious.

💬 What’s your biggest sourdough challenge? Share your experience or ask questions in the comments—let’s grow better bread together.