Why Does My Sourdough Bread Collapse In The Oven Baking Science Decoded

Sourdough bread is a marvel of natural fermentation and artisanal craftsmanship. When executed well, it yields a loaf with an open crumb, crisp crust, and complex flavor. But even experienced bakers face a frustrating issue: the loaf rises beautifully in the oven—only to deflate or collapse before cooling. This phenomenon can feel like a betrayal after hours of careful preparation. The truth is, sourdough collapse isn’t random; it’s rooted in precise baking science. Understanding the interplay of gluten structure, gas retention, fermentation, and heat can transform your baking from inconsistent to reliable.

The Science of Oven Spring and Collapse

Oven spring refers to the rapid expansion of dough during the first 10–15 minutes of baking. This occurs because heat causes trapped carbon dioxide and alcohol vapor to expand, while yeast experiences a final burst of activity before dying at around 140°F (60°C). Simultaneously, steam softens the dough surface, allowing it to stretch without cracking.

However, if the internal structure of the dough cannot support this expansion, the loaf collapses. Collapse typically happens when the gluten network weakens too soon, the dough is over-fermented, or the crust sets too slowly. The structural integrity of the loaf must balance elasticity and strength throughout the bake. If one element fails, the entire structure may give way.

Think of your sourdough like a balloon filled with air. A strong, elastic balloon stretches evenly and holds its shape. But if the rubber is too thin or overstretched, it bursts. Similarly, dough that lacks strength or has been over-expanded will rupture under internal pressure.

Tip: Perform the \"poke test\" before baking: gently press the dough. If it springs back slowly and leaves a slight indentation, it's ready. If it doesn't spring back, it's over-proofed.

Common Causes of Sourdough Collapse

1. Over-Fermentation (Over-Proofing)

One of the leading reasons for collapse is over-proofing. When dough ferments too long, the gluten network breaks down due to enzymatic activity and acid buildup from lactic and acetic acids. While some acidity enhances flavor, excessive fermentation weakens the protein matrix responsible for holding gas bubbles.

Over-proofed dough feels fragile, jiggly, and lacks resilience. In the oven, it expands rapidly but cannot sustain the volume because the supporting structure has degraded. The result is a dramatic rise followed by a sunken center or side collapse.

2. Weak Gluten Development

Gluten forms when flour proteins (glutenin and gliadin) hydrate and align through mechanical action—mixing, folding, and kneading. Without sufficient development, the dough lacks tensile strength and elasticity.

This is especially common in high-hydration doughs (75% hydration or more), where water dilutes the protein concentration and makes alignment harder. Bakers who skip folds or mix too briefly often end up with dough that spreads rather than rises vertically.

3. Inadequate Scoring

Scoring isn’t just decorative—it’s functional. Cuts in the dough’s surface control where expansion occurs during oven spring. Without proper scoring, steam and gases escape unpredictably, often causing blowouts or uneven expansion that destabilizes the loaf.

A poorly scored loaf may expand sideways instead of upward, leading to flattening. Deep, decisive cuts at a 30–45° angle allow for controlled release and vertical lift.

4. Incorrect Oven Temperature or Lack of Steam

Steam in the first phase of baking keeps the dough surface moist and pliable, delaying crust formation. Without steam, the crust hardens too early, restricting expansion. Conversely, if the oven is too cool, yeast activity prolongs, over-inflating the dough before the structure sets.

On the other hand, an oven that’s too hot can cause exterior charring while the interior remains weak, increasing collapse risk. Ideal sourdough baking temperature ranges between 450°F and 475°F (230°C–245°C) with steam for the first 20 minutes.

5. Excessive Hydration Without Support

High hydration increases openness in the crumb but demands stronger gluten and better shaping technique. Dough with 80%+ hydration is inherently less stable. Without proper pre-shaping, tension during final shaping, or use of supportive vessels like bannetons, such loaves are prone to spreading and collapsing.

“Many home bakers chase high hydration for the ‘artisan look’ but neglect the structural prerequisites. Strength comes before slack.” — Dr. Lin Wei, Food Scientist & Artisan Baker

Step-by-Step Guide to Prevent Collapse

To consistently produce well-risen, structurally sound sourdough, follow this evidence-based sequence:

1. Use a mature, active starter: Feed your starter 8–12 hours before mixing. It should double within 4–6 hours and pass the float test. An immature starter leads to slow, uneven fermentation.
2. Autolyse for 30–60 minutes: Mix flour and water and let rest before adding salt and starter. This improves gluten development and hydration, reducing mixing time.
3. Knead or perform coil folds: Conduct 3–4 sets of coil folds spaced 30 minutes apart during bulk fermentation. This builds strength gradually without overworking the dough.
4. Monitor fermentation time and temperature: Bulk ferment at 75°F–78°F (24°C–26°C) for 3.5–5 hours. Cooler temperatures extend fermentation safely; warmer ones accelerate it but increase collapse risk.
5. Shape with surface tension: Pre-shape first, rest 20–30 minutes, then final shape tightly. Rotate the dough in your hands to create a taught outer skin that resists over-expansion.
6. Proof in a banneton: Use lined, floured baskets to support the dough’s shape. For cold proofing, refrigerate for 8–16 hours. Cold slows fermentation, preserving structure.
7. Score deeply and confidently: Use a razor or lame at a shallow angle. One or two bold slashes work better than multiple shallow ones.
8. Bake with steam and proper heat: Preheat Dutch oven or baking stone for 1 hour at 475°F (245°C). Add dough, cover, and reduce heat to 450°F (230°C). Bake covered for 20 minutes, then uncovered for 20–25 minutes.

Tips and Best Practices Table

Factor	Do’s	Don’ts
Fermentation Time	Proof until slightly puffy, not doubled	Don’t let dough rise overnight at room temp without refrigeration
Gluten Development	Perform 3–4 coil folds during bulk fermentation	Don’t skip folds or under-mix high-hydration doughs
Shaping	Create tight surface tension; use bench scraper	Don’t handle dough roughly or deflate excessively
Oven Environment	Use steam for first 20 min; preheat thoroughly	Don’t open oven door early; avoid low temperatures
Hydration	Start with 70–75%; increase only after mastering basics	Don’t jump to 80%+ hydration without building skill

Real Example: From Collapse to Confidence

Jessica, an avid home baker in Portland, struggled for months with collapsed loaves. Her dough looked perfect during bulk fermentation and rose impressively in the banneton, but every time she opened the oven, the crown had caved in.

She reviewed her process and discovered two issues: First, she was leaving her dough to proof on the counter for 14 hours in a warm kitchen (80°F/27°C), leading to over-fermentation. Second, she wasn’t performing coil folds, assuming autolyse and stretch-and-folds were enough.

After switching to a 4-hour bulk ferment with four coil folds and moving to an overnight cold proof in the fridge, her results transformed. Her next loaf sprung evenly, held its shape, and developed a glossy ear along the score. “I realized I was treating sourdough like a set recipe instead of a living system,” she said. “Once I respected the timing and strength-building, everything changed.”

Checklist: Prevent Sourdough Collapse

• ✅ Starter is active and fed 8–12 hours prior
• ✅ Autolyse completed for optimal gluten formation
• ✅ 3–4 sets of coil folds performed during bulk fermentation
• ✅ Bulk fermentation time adjusted for ambient temperature
• ✅ Final shape has tight surface tension
• ✅ Proofed in a floured banneton, preferably cold
• ✅ Scored with a sharp blade at 30–45° angle
• ✅ Oven and vessel preheated for at least 60 minutes
• ✅ Steam used in first 20 minutes of baking
• ✅ Loaf baked to internal temperature of 205°F–210°F (96°C–99°C)

Frequently Asked Questions

Can I rescue a collapsed sourdough loaf?

If the loaf collapses late in the bake (after 30+ minutes), it may still be edible—though flat. Slice and toast it; the flavor likely remains excellent. However, early collapse often indicates over-fermentation or weak structure, which affects texture. You can repurpose it into croutons or breadcrumbs. Prevention is always better than rescue.

Does flour type affect collapse risk?

Yes. High-protein bread flour (12–14% protein) provides more gluten strength than all-purpose or whole wheat flour. Whole grains contain bran, which cuts gluten strands and weakens structure. If using whole wheat, blend with bread flour (e.g., 50/50) and consider shorter fermentation times.

Why did my loaf rise in the oven but fall as soon as I took the lid off?

This is typically due to premature removal of steam or insufficient internal structure. When you remove the Dutch oven lid, the sudden exposure to dry heat can shock a still-fragile crumb. Ensure the loaf has baked covered for at least 20 minutes and reaches at least 190°F (88°C) internally before uncovering. Finishing uncovered allows the crust to firm up and support the loaf.

Mastery Through Understanding

Sourdough collapse is not a mystery—it’s a signal. Each deflated loaf communicates something about fermentation, strength, or environment. By learning to read these signs, you shift from guessing to controlling the process. Baking becomes less about luck and more about precision and observation.

The beauty of sourdough lies in its responsiveness. Adjust one variable—proofing time, fold frequency, oven steam—and the outcome changes. This sensitivity demands respect, but it also offers immense reward. A perfectly risen, golden-brown loaf with a crackling crust and airy crumb is not just food; it’s a testament to patience, science, and craft.

💬 Have you cracked the code on sourdough collapse? Share your breakthrough moment or favorite tip in the comments—your insight could help another baker rise above the slump.