Why Does My Sourdough Deflate Before Baking And How To Get That Perfect Rise

Sourdough bread is revered for its tangy flavor, chewy crumb, and crisp crust—but achieving that ideal open structure and sky-high oven spring can feel elusive. One of the most frustrating moments in sourdough baking is watching your carefully proofed loaf collapse just before it hits the oven. This deflation isn’t random; it’s a signal from your dough, indicating an imbalance in fermentation, strength, or handling. Understanding the root causes and applying targeted fixes can transform your results from flat loaves to bakery-quality boules.

The journey from starter to finished loaf involves a delicate interplay of time, temperature, gluten development, and yeast activity. When any of these elements fall out of sync, your dough may overproof, lose structural integrity, or fail to retain gas—leading to deflation. The good news: with precise adjustments, you can stabilize your process and consistently produce tall, airy sourdough with dramatic oven spring.

Understanding Why Sourdough Deflates Before Baking

Deflation occurs when the gluten network in your dough can no longer support the carbon dioxide produced by fermentation. As gas builds up during proofing, the dough expands. But if the structure weakens—due to overproofing, poor gluten development, or physical shock—the bubbles coalesce and burst, causing the loaf to collapse.

The primary reasons for pre-bake deflation include:

• Overproofing: Extended fermentation breaks down gluten and exhausts available sugars, weakening the dough’s ability to hold shape.
• Weak gluten development: Insufficient kneading, mixing, or folding fails to build a strong network capable of trapping gas.
• Inconsistent temperature: Warm environments accelerate fermentation, increasing the risk of overproofing.
• Rough handling: Transferring or scoring an overproofed or fragile dough can puncture gas pockets.
• Underripe or weak starter: An inactive levain doesn’t provide enough lift, leading to unstable fermentation dynamics.

Each of these factors affects the balance between gas production and structural resilience. A healthy sourdough must generate gas *and* contain it until the moment of baking, when heat rapidly expands the air pockets—a phenomenon known as oven spring.

Tip: Perform the \"poke test\" to check proofing readiness: gently press the dough with a fingertip. If it springs back slowly and leaves a slight indentation, it's ready. If it doesn't rebound or collapses, it's overproofed.

Building Dough Strength: The Foundation of Rise

No amount of careful proofing can compensate for weak dough structure. Gluten forms the scaffolding that traps fermentation gases. Without sufficient strength, even perfectly timed proofing will result in flattening.

To build robust gluten networks, focus on three key practices:

1. Autolyse: Mix flour and water and let rest for 20–60 minutes before adding salt and starter. This allows hydration and initial gluten formation without mechanical stress.
2. Folding: Perform 3–4 sets of stretch-and-folds during bulk fermentation (every 30 minutes in the first two hours). This aligns gluten strands and strengthens elasticity.
3. Final shaping: Shape tightly to create surface tension. Use bench scrapers and cupped hands to pull the dough toward you, sealing the base underneath.

Different flours impact strength. High-protein bread flour (12–14% protein) provides more gluten than all-purpose or whole grain varieties. If using whole wheat or rye, blend with bread flour to maintain structure.

“Gluten isn’t just about elasticity—it’s about endurance. Your dough must withstand hours of fermentation without tearing.” — Dr. Linnea Henriksson, Food Scientist & Artisan Baker

Mastering Fermentation: Timing, Temperature, and Starter Maturity

Fermentation is the engine of sourdough rise. But too much or too little activity derails the process. The goal is balanced fermentation: enough gas production to leaven the bread, but not so much that it compromises dough integrity.

Your starter’s maturity plays a pivotal role. A starter used at peak activity—typically 4–8 hours after feeding, when it has doubled and shows bubbles throughout—delivers consistent leavening power. Using it too early (before peak) or too late (after collapse) leads to unpredictable fermentation rates.

Environmental temperature directly affects speed. At 75°F (24°C), bulk fermentation may take 4–5 hours. At 80°F (27°C), it could finish in 3 hours. Cooler temperatures slow fermentation, giving more control and deeper flavor development.

Room Temp (°F)	Bulk Fermentation Time	Risk Level
68–72°F	5–6 hours	Low – Ideal for control
73–77°F	4–5 hours	Moderate – Monitor closely
78°F+	2.5–3.5 hours	High – Overproofing likely

Similarly, final proofing conditions matter. Many bakers use a refrigerator (retarding) for 8–12 hours overnight. Cold slows yeast activity while allowing enzymatic flavor development. Retarded dough is less prone to overproofing and often delivers superior oven spring due to the thermal shock of going from cold to hot oven.

Tip: If your kitchen runs warm, refrigerate the dough earlier in bulk fermentation (e.g., after 2 hours at room temp) to prevent runaway fermentation.

Step-by-Step Guide to Prevent Deflation and Maximize Rise

Follow this structured approach to ensure your sourdough maintains volume and achieves maximum oven spring:

1. Feed your starter 6–8 hours before mixing. Use equal parts flour, water, and starter (1:1:1 ratio). Let it sit at room temperature until bubbly and doubled.
2. Weigh ingredients precisely. Use a digital scale for consistency. Typical hydration: 70–75% (e.g., 700–750g water per 1000g flour).
3. Autolyse for 30 minutes. Combine flour and water; rest covered. Add starter and salt afterward.
4. Perform four sets of stretch-and-folds. Do one every 30 minutes during the first 2 hours of bulk fermentation.
5. Monitor bulk fermentation duration. Total time depends on temperature and starter strength. Look for a 30–50% increase in volume, visible bubbles, and a jiggly, domed surface.
6. Shape tightly and place in a well-floured banneton. Use rice flour to prevent sticking. For round loaves, create surface tension by rotating and tucking under.
7. Proof wisely: Choose room-temperature proof (2–4 hours) or cold retard (8–16 hours in fridge). Cold proofing reduces overproofing risk.
8. Preheat oven and baking vessel. Heat Dutch oven at 450–475°F (230–245°C) for at least 45 minutes.
9. Score just before baking. Use a sharp blade at a 30-degree angle. One decisive cut prevents dragging and deflation.
10. Bake with steam. Cover for first 20–25 minutes, then uncover to crisp crust.

This method prioritizes structure, controlled fermentation, and thermal shock—all essential for preserving gas and maximizing rise.

Real Example: From Flat Loaf to Perfect Boule

Jess, an avid home baker in Austin, Texas, struggled for months with collapsing sourdough. Her kitchen averaged 78–80°F, and she was using her starter straight from the fridge. She bulk fermented for 5 hours at room temperature, then proofed for another 3 hours. Every loaf flattened during scoring.

After adjusting her process—feeding her starter 8 hours ahead, reducing bulk fermentation to 3.5 hours, and switching to an overnight cold proof in the banneton—her results transformed. The cooler fermentation preserved gluten strength, and the cold dough held its shape during transfer and scoring. Her next bake had a 2-inch oven spring and an open, even crumb.

The change wasn’t in her skill, but in understanding how environment and timing affect dough behavior. Once she aligned her routine with her climate, success followed.

Do’s and Don’ts: Quick Reference Table

Action	Do	Don’t
Starter Use	Use at peak ripeness (doubled, bubbly)	Use right after feeding or when collapsed
Handling Proofed Dough	Gentle, confident movements	Shake, drop, or rough-transfer
Shaping	Create tight surface tension	Leave seams open or shape loosely
Proofing Environment	Cool area or refrigerator	Hot spot near oven or sunlight
Scoring	Swift, shallow cuts with razor	Deep, hesitant slashes with dull knife

Frequently Asked Questions

Can I rescue a deflated sourdough loaf?

If caught early—before baking—you may be able to reshape and reproof for 1–2 hours. However, the gluten may already be compromised, resulting in denser texture. For future batches, shorten proofing times or strengthen folds.

Why does my dough rise well in bulk but collapse during final proof?

This suggests overdevelopment during bulk fermentation. While some expansion is expected, excessive gas weakens gluten. Limit bulk fermentation to 40–50% volume increase and rely more on final proof for rise.

Does high hydration always lead to deflation?

Not necessarily. High hydration (80%+) requires stronger gluten development and often benefits from longer autolyse and extra folds. Beginners should start at 70–75% hydration to build confidence in handling and structure.

Key Takeaways and Action Plan

Consistently achieving a well-risen sourdough loaf hinges on three pillars: dough strength, fermentation control, and gentle handling. Deflation is not a failure of effort, but a feedback mechanism pointing to where adjustments are needed.

Start by auditing your current process:

• Is your starter peaking when used?
• Are you folding sufficiently during bulk fermentation?
• Is your kitchen temperature affecting timing?
• Are you relying on time instead of signs of readiness?

Implement one change at a time. Switch to cold proofing. Adjust fold frequency. Calibrate your starter schedule. Small tweaks yield dramatic improvements.

“The best sourdough isn’t the one that follows a recipe exactly—it’s the one whose baker listens to the dough.” — Chad Robertson, Tartine Bakery

Conclusion: Bake with Confidence

Deflation doesn’t mean you’ve failed—it means you’re learning the language of sourdough. Each collapse teaches you about gluten, fermentation, and timing. By building stronger dough, respecting your starter’s rhythm, and mastering temperature, you’ll consistently produce loaves that rise proudly in the oven and slice with a satisfying spring.

Now is the time to apply these insights. Adjust your next bake using the checklist above, track your changes, and observe the results. Share your journey, your triumphs, and even your flat loaves—they’re all steps toward mastery.

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