Why Does My Sourdough Bread Collapse In The Oven And How To Prevent It

Sourdough bread is a marvel of natural fermentation—complex, flavorful, and deeply satisfying when done right. But few things are more disheartening than watching your carefully nurtured loaf rise beautifully in the banneton, only to deflate dramatically during or just after oven spring. A collapsed sourdough isn’t necessarily inedible, but it signals structural instability that affects both appearance and texture.

Understanding why this happens requires diving into the interplay between gluten development, fermentation, shaping technique, and oven dynamics. The good news: most causes of collapse are predictable—and fixable. With precise adjustments, you can consistently produce loaves that spring confidently in the oven and hold their shape from scoring to cooling.

The Science Behind Oven Collapse

When sourdough enters a hot oven, it undergoes \"oven spring\"—a final burst of expansion driven by trapped gases (mainly CO₂) expanding and steam production within the dough. This phase lasts roughly 15–20 minutes, after which the crust sets and the crumb structure stabilizes. If the loaf collapses during or immediately after this stage, it means the internal structure couldn’t support the pressure.

Think of your dough like a balloon made of mesh. During bulk fermentation and proofing, yeast and bacteria produce gas that inflates the gluten network. If the mesh is too weak, over-stretched, or compromised by over-fermentation, it will tear rather than expand evenly. Once the heat hits, any existing flaws become critical failure points.

Common triggers for collapse include:

• Over-fermentation: Excess gas production stretches gluten beyond recovery.
• Poor gluten development: Weak structure fails under pressure.
• Under-proofing followed by aggressive handling: Sudden release of tension causes uneven expansion.
• Inadequate scoring: Restricts controlled expansion, leading to blowouts.
• Low oven temperature or lack of steam: Delays crust formation, allowing uncontrolled spread.

Each of these factors can act alone or compound one another. Fixing collapse isn't about one magic trick—it's about refining your entire process for structural integrity.

Tip: Perform the \"float test\" cautiously—it’s not reliable for determining proof readiness. Instead, use the finger press test: gently poke the dough. If it springs back slowly and leaves a slight indentation, it’s ready. If it fills back instantly, it needs more time; if it doesn’t spring back at all, it’s over-proofed.

Key Causes and How to Fix Them

1. Over-Fermentation (Bulk or Final Proof)

Fermenting too long is the single most common cause of collapse. When dough ferments past its peak, the acids produced by wild yeast and lactobacilli begin to degrade gluten. The network loses elasticity and turns slack. While it may look puffy, it lacks strength.

This often happens when bakers rely solely on time instead of observing dough behavior. Room temperature, starter strength, hydration, and flour type all influence fermentation speed.

“Many home bakers treat sourdough like a clock-driven recipe. But real control comes from reading the dough—not the timer.” — Dr. Richard Rivera, Artisan Bread Researcher, UC Davis Fermentation Lab

To avoid over-fermentation:

• Monitor dough volume—ideal bulk rise is 30–50% increase for high-hydration doughs, up to 80–100% for lower hydration.
• Check for signs: shiny surface, domed top, gentle jiggle without sagging.
• Adjust room temperature: cooler slows fermentation, giving more control.

2. Insufficient Gluten Development

No amount of careful proofing can save dough with weak gluten. Proper development creates a strong, elastic web capable of trapping gas without tearing.

Modern all-purpose flours often lack the protein content needed for robust sourdough. Bread flour (12–13% protein) or adding vital wheat gluten helps significantly. Kneading technique also matters—especially in low-intervention methods like stretch and folds.

For optimal gluten formation:

1. Autolyse flour and water for 30–60 minutes before adding starter and salt.
2. Perform 4–6 sets of stretch and folds during bulk fermentation, spaced 20–30 minutes apart.
3. Ensure full incorporation of ingredients—no dry pockets or shaggy texture.

3. Poor Shaping Technique

Shaping isn’t just about aesthetics—it seals the surface tension necessary to contain internal pressure. A loose or uneven shape creates weak spots where gas escapes violently during baking.

Watch for these red flags:

• Dough spreads out instead of holding a taut round or oval.
• Seams don’t stay sealed after placing in banneton.
• Top surface feels floppy, not drum-tight.

Proper shaping involves degassing gently, pre-shaping into a tight round, resting for 15–20 minutes, then final shaping with deliberate tension on the underside.

4. Inadequate Scoring

Scoring gives the loaf a controlled exit route for steam and gas. Without it, pressure builds until it ruptures the weakest point—often the side or bottom.

Use a sharp lame or razor at a 30–45° angle, cutting ½ to ¾ inch deep. One decisive slash is often enough for batards; boules may need multiple cuts. Avoid shallow or hesitant strokes—they don’t penetrate deeply enough to guide expansion.

5. Oven Conditions: Heat and Steam

Oven spring depends on rapid initial heat transfer. If the oven isn’t hot enough—or heats unevenly—the dough expands slowly, weakening structure before the crust sets.

Ideal baking conditions:

• Preheat oven to 475°F (245°C) or higher for at least 45 minutes.
• Use a Dutch oven or combo cooker to trap steam and mimic professional ovens.
• Bake covered for first 20 minutes, then uncover to finish drying the crust.

Steam keeps the surface pliable during early expansion. Without it, the crust hardens too soon, restricting rise and increasing risk of cracking or collapse.

Step-by-Step Guide to Prevent Collapse

Follow this refined workflow to build resilience into every loaf:

1. Start with strong flour: Use bread flour or blend in 10–15% whole grain for flavor without sacrificing strength.
2. Autolyse: Mix flour and water; rest 30–60 minutes before adding starter and salt.
3. Bulk ferment: Perform 4–6 stretch and folds over 3–4 hours. Watch for volume gain and smooth texture.
4. Divide and pre-shape: Gently portion dough, form into tight rounds, and bench rest 15–20 minutes.
5. Final shape: Create surface tension by folding edges underneath and rolling forward with firm pressure.
6. Proof: Place seam-side up in floured banneton. Refrigerate overnight (preferred) or room temp for 2–4 hours. Test with finger press.
7. Bake: Preheat Dutch oven at 475°F (245°C) for 45+ minutes. Score deeply, transfer carefully, cover, and bake 20 min. Uncover, reduce to 450°F (230°C), bake 20–25 min more.
8. Cool: Wait at least 2 hours before slicing to allow crumb stabilization.

This method prioritizes strength, control, and consistency—minimizing variables that lead to collapse.

Do’s and Don’ts: Quick Reference Table

Do	Don’t
Use bread flour or high-protein blend	Rely solely on all-purpose flour for wet doughs
Perform stretch and folds every 30 minutes	Skip gluten-building steps
Proof in the fridge for better control	Leave dough at room temp overnight
Score with a sharp blade at 45° angle	Make shallow, timid cuts
Preheat oven and vessel thoroughly	Put dough into a cold or underheated oven

Real Example: From Flop to Spring

Sarah, a home baker in Portland, struggled for months with flat, pancake-like loaves. Her dough looked perfect in the banneton but would spread sideways in the oven, losing all height. She followed recipes exactly—same time, same flour, same schedule.

After recording her process, she noticed two issues: her kitchen was warm (78°F), causing her final proof to go 2 hours too long. And she wasn’t pre-shaping—going straight from bulk fermentation to final shape, resulting in poor surface tension.

She adjusted: moved final proof to the refrigerator after shaping, reduced room-temp bulk ferment by 1 hour, and added a pre-shape step with a 20-minute rest. Her next loaf rose 40% higher and held its shape perfectly. “I thought I needed a new Dutch oven,” she said. “Turns out, I just needed to slow down and tighten up.”

Essential Checklist for Stable Loaves

Before every bake, run through this checklist:

• ✅ Used flour with at least 12% protein?
• ✅ Performed autolyse and adequate stretch and folds?
• ✅ Monitored bulk fermentation by feel and volume—not just time?
• ✅ Pre-shaped and allowed bench rest before final shaping?
• ✅ Created taut surface tension during shaping?
• ✅ Proofed properly (refrigerated preferred)?
• ✅ Tested proof readiness with finger press?
• ✅ Preheated oven and baking vessel for 45+ minutes?
• ✅ Scored deeply and confidently before loading?
• ✅ Baked covered initially to retain steam?

Missing even one item can tip the balance toward collapse. Consistency across all stages is key.

Frequently Asked Questions

Can I rescue an over-proofed loaf?

Sometimes. If caught early, gently reshape the dough and refrigerate for 2–3 hours to re-tighten the gluten. This won’t fully restore strength, but it can salvage some oven spring. Fully collapsed dough is best repurposed into crackers or focaccia.

Why does my loaf rise well but still collapse at the end?

Late-stage collapse often points to insufficient crust set. If your oven runs cool or you remove the lid too early, the structure hasn’t stabilized. Try extending covered bake time by 5 minutes or using an oven thermometer to verify actual temperature.

Does hydration level affect collapse?

Absolutely. Dough above 75% hydration is much more prone to spreading due to weaker gluten support. If you're new to sourdough, start with 65–70% hydration to build confidence in handling and shaping before moving to wetter doughs.

Conclusion: Build Strength, Not Just Air

A collapsing sourdough loaf isn’t a failure—it’s feedback. Each deflation reveals where your process needs refinement. The goal isn’t just to make bread that rises, but bread that holds its promise from bowl to table.

Mastery lies in balancing fermentation energy with structural restraint. It’s found in the tension of a well-shaped boule, the precision of a clean score, and the patience of proper timing. These aren’t shortcuts—they’re skills that compound with every bake.

💬 What’s your biggest sourdough challenge? Share your experience below—whether it’s sticky dough, pale crust, or another collapse story. Let’s troubleshoot together and help each other grow as bakers.