Why Does My Sourdough Bread Collapse In The Oven Troubleshooting Hydration Levels

Sourdough baking is both an art and a science. When your loaf rises beautifully during fermentation only to deflate dramatically in the oven, it can be disheartening. One of the most common culprits behind this collapse is improper hydration—either too high or poorly managed. While hydration is essential for creating an open crumb and chewy texture, getting it wrong compromises structural integrity. Understanding how water interacts with flour, gluten development, and gas retention reveals why balance is critical. This guide breaks down the mechanics of collapse, identifies hydration-related causes, and offers actionable solutions to help you bake consistently resilient loaves.

The Role of Hydration in Sourdough Structure

Hydration refers to the ratio of water to flour in a dough, expressed as a percentage. A 75% hydration dough contains 75 grams of water for every 100 grams of flour. Higher hydration leads to a more fluid, extensible dough that can expand easily during oven spring. However, without sufficient strength, that same dough may lack the ability to hold its shape under heat stress.

When dough enters the oven, trapped carbon dioxide expands rapidly, and steam softens the crust, allowing the loaf to rise further—a phase known as “oven spring.” If the gluten network isn’t strong enough to contain this expansion, the structure fails, resulting in collapse. Excess hydration weakens gluten by increasing mobility between protein strands, making them more prone to overstretching and rupture.

Flour type also plays a role. High-protein flours like bread flour or strong white flour form stronger gluten networks and tolerate higher hydration better than all-purpose or whole grain flours, which absorb more water but offer less elasticity.

Tip: Start with a moderate hydration (70–75%) when troubleshooting. It’s easier to adjust upward once you’ve mastered structure.

How Excessive Hydration Causes Collapse

When hydration exceeds what the flour can structurally support, several issues arise:

• Weak gluten matrix: Too much water dilutes gluten proteins, reducing their ability to link into a cohesive, elastic web.
• Poor gas retention: Bubbles formed during fermentation grow too large and coalesce, weakening surrounding dough walls.
• Over-spread during proofing: Wet dough spreads outward rather than rising upward, leading to flat loaves that collapse under their own weight in the oven.
• Delayed crust formation: High moisture content slows crust hardening, extending the window when internal pressure can deform the loaf.

A dough at 80%+ hydration demands advanced handling techniques—frequent stretch-and-folds, longer bulk fermentation with temperature control, and precise scoring. Without these, even a well-fermented dough can fail catastrophically in the oven.

“Hydration isn’t just about wetness—it’s about balance between liquidity and strength. A dough that feels alive but holds its shape is on the right track.” — Daniel Leader, artisan baker and author of Bread Alone

Diagnosing Hydration Issues: A Step-by-Step Guide

Follow this timeline to identify whether hydration is contributing to your loaf’s collapse:

1. Observe dough consistency after mixing: Does it immediately spread like batter? If so, hydration may be too high for your flour type.
2. Evaluate during bulk fermentation: Is the dough domed and firm, or flat and slack? Properly hydrated dough should dome slightly and resist gentle poking.
3. Check preshape and final shape: Can you pre-shape into a taut round? If the dough tears or won’t tighten, it lacks strength—possibly due to excess water.
4. Assess proofed loaf before baking: Does it hold height in the banneton, or has it flattened? A collapsed pre-bake loaf often indicates structural weakness from over-hydration.
5. Watch oven spring: Does the loaf rise sharply then sink, or maintain its peak? Rapid rise followed by fall suggests the structure couldn’t contain internal pressure.

Adjustments should be made incrementally. Reducing hydration by 5% can make a significant difference in manageability and oven performance.

Hydration Guidelines by Flour Type

Different flours absorb water differently. The ideal hydration level depends on your base ingredient. Use this reference table to align hydration with flour strength:

Flour Type	Recommended Hydration Range	Notes
All-Purpose Flour	65–70%	Limited gluten strength; best for beginners. Higher hydration risks collapse.
Bread Flour	70–78%	Higher protein supports open crumb and better oven spring.
Whole Wheat Flour	75–80%	Absorbs more water but weaker gluten. Combine with bread flour for stability.
Rye Flour (light)	70–75%	Low gluten; requires blending with wheat flour to prevent collapse.
High-Extraction / Hybrid Flours	73–77%	Balances nutrition and strength. Monitor dough feel closely.

Always weigh ingredients. Volume measurements vary widely and can unintentionally increase hydration. For example, spooned vs. scooped flour can differ by up to 20%, drastically altering hydration percentages.

Real Example: From Collapse to Confidence

Julia, a home baker in Portland, struggled for months with flat, pancake-like sourdough. Her recipe used 80% hydration with all-purpose flour, folded three times during bulk fermentation. The dough looked impressive—bubbly and jiggly—but collapsed within minutes of entering the oven.

After consulting a local bakery, she adjusted her approach: switching to 72% hydration using a 50/50 blend of bread flour and all-purpose, adding one extra set of stretch-and-folds, and reducing final proof time by 45 minutes. The result? A loaf with pronounced oven spring, crisp crust, and no collapse. She later increased hydration to 76% once her shaping technique improved, proving that progression matters more than chasing high numbers.

Her experience underscores a key principle: hydration must match skill level, flour choice, and environmental conditions. What works for one baker may fail for another without context.

Troubleshooting Checklist: Prevent Oven Collapse

Use this checklist to systematically address hydration-related collapse:

• ✅ Weigh all ingredients using a digital scale
• ✅ Match hydration level to flour protein content
• ✅ Perform adequate stretch-and-folds (4–6 sets over 2 hours)
• ✅ Ensure dough passes the “windowpane test” before final shaping
• ✅ Pre-shape and bench rest to build surface tension
• ✅ Final shape should feel taut and resist indentation
• ✅ Proof in a lined banneton with proper seam-up orientation
• ✅ Avoid over-proofing—use the “poke test” (dough springs back slowly)
• ✅ Score deeply (½ inch) and confidently to allow controlled expansion
• ✅ Bake in a preheated Dutch oven for optimal steam and heat transfer

One overlooked factor is fermentation temperature. Warm environments accelerate yeast activity, potentially over-proofing dough even if timing appears correct. Cooler room temperatures (72–75°F) give better control over gas production and dough strength.

Tip: If your dough feels too slack, try reducing hydration by 5% and adding an extra fold. Small changes yield big improvements.

Other Factors That Contribute to Collapse

While hydration is central, other elements interact with it to influence structural integrity:

• Under-developed gluten: Insufficient kneading or folding leaves the network fragile, especially in high-hydration doughs.
• Over-fermentation: Extended bulk or final proof breaks down gluten, turning strong dough into mush regardless of hydration.
• Poor shaping technique: Loose shaping fails to create surface tension, causing the loaf to spread instead of rise.
• Inadequate scoring: Shallow or hesitant cuts restrict steam release, forcing the loaf to burst unpredictably and lose shape.
• Oven temperature too low: Delayed oven spring allows structure to weaken before full expansion occurs.

These factors compound hydration issues. For instance, a 78% hydration dough might succeed with perfect folds and cool fermentation but collapse if left to proof overnight at 80°F.

Frequently Asked Questions

Can I fix a too-wet dough after mixing?

Yes, but carefully. Add small amounts of flour (5–10g at a time) during early bulk fermentation while performing stretch-and-folds. Avoid adding large quantities, as this disrupts fermentation balance. Alternatively, proceed with extra folds to strengthen the dough without altering hydration.

Why did my low-hydration loaf collapse?

Even drier doughs (65–70%) can collapse if over-proofed or poorly shaped. Low hydration doesn’t guarantee success—it simply makes structure easier to manage. Check fermentation timing and shaping tension if using lower water ratios.

Does humidity affect dough hydration?

Indirectly. High ambient humidity may slow evaporation during proofing, slightly increasing surface moisture. More importantly, flour stores moisture based on environment. Flour kept in a humid kitchen absorbs more water, effectively increasing hydration even with the same recipe. Store flour in airtight containers to minimize variability.

Conclusion: Master Hydration, Master Your Loaf

Collapsing sourdough isn’t a failure—it’s feedback. Hydration is a powerful variable, but it must work in harmony with flour strength, fermentation control, and mechanical development. By tuning your water-to-flour ratio to match your ingredients and skill level, you gain greater predictability in the oven. Start moderate, observe closely, and adjust deliberately. Each bake becomes a step toward mastery.

💬 Have a collapse story or breakthrough tip? Share your experience below—your insight could help another baker rise above the flattest of failures.