Why Is My Sourdough Bread Always Flat Troubleshooting Guide

Sourdough baking is both an art and a science. When done right, the result is a beautifully risen loaf with a crisp crust and an open, airy crumb. But if your sourdough consistently turns out flat—lacking height, structure, or oven spring—it can be frustrating. The good news is that flat loaves are rarely due to one single issue. More often, they stem from a combination of factors related to fermentation, gluten development, shaping, or baking technique. This guide dives deep into the most common causes and provides actionable solutions so you can bake reliably high-rising sourdough.

Understanding Why Sourdough Rises (and Why It Sometimes Doesn’t)

Sourdough relies on natural fermentation. Wild yeast and lactic acid bacteria in your starter consume flour and produce carbon dioxide gas. This gas gets trapped in a network of gluten developed during mixing and bulk fermentation, causing the dough to expand. When baked, the heat rapidly expands the gas (oven spring), setting the structure as the starches gelatinize and proteins coagulate.

A flat loaf means the dough either couldn't hold gas effectively, didn’t produce enough gas, or lost gas before or during baking. Identifying where in the process this breakdown occurs is key to fixing it.

Tip: Always perform a float test before mixing your final dough to confirm your starter is active and ready.

1. Starter Strength and Fermentation Timing

Your sourdough starter is the engine behind the rise. If it’s weak or underfed, it won’t generate enough gas to leaven the dough properly. A sluggish starter leads to poor volume and dense, flat bread.

Signs of a weak starter include slow rise after feeding, lack of bubbles, or a strong alcoholic smell indicating overfermentation. Using a starter at its peak activity—usually 4–8 hours after feeding, depending on temperature—is crucial. Using it too early or too late reduces its leavening power.

To optimize starter performance:

• Feed your starter regularly with equal parts flour and water by weight (1:1 ratio).
• Use it when it has doubled in volume and shows lots of bubbles throughout.
• Keep it in a warm spot (75–80°F / 24–27°C) for faster, more predictable activity.

“Your starter should be predictably active before you even think about mixing dough. Inconsistent starters lead to inconsistent loaves.” — Ken Forkish, author of *Flour Water Salt Yeast*

2. Gluten Development and Dough Structure

Gluten forms the elastic net that traps gas. Without sufficient strength, the dough collapses under its own weight or fails to expand in the oven.

Underdeveloped gluten is a common cause of flat loaves. This happens when there isn’t enough mixing, folding, or time for the dough to build structure. Conversely, overmixing or overproofing can break down gluten, also leading to collapse.

To assess gluten development, perform the “windowpane test”: stretch a small piece of dough between your fingers. If it forms a thin, translucent membrane without tearing, the gluten is well-developed.

Folding Techniques to Improve Structure

Incorporating stretch-and-folds during bulk fermentation strengthens the dough gently. For most recipes, 3–4 sets of folds over 1.5 to 2 hours work well:

1. After 30 minutes of rest post-mixing, grab one side of the dough, stretch it upward, and fold it over the center.
2. Rotate the bowl 90 degrees and repeat three more times.
3. Repeat every 30 minutes for 2–3 additional sets.

Tip: Wet hands prevent sticking during folding. Don’t rush—gentle handling preserves gas bubbles.

3. Proofing: Too Long, Too Short, or Just Wrong?

Proofing is one of the most misunderstood stages. Both underproofing and overproofing can result in flat bread, but for different reasons.

Underproofed dough hasn’t fermented long enough to develop sufficient gas. It may appear tight and resist shaping, and while it might spring up initially in the oven, it lacks expansion capacity and remains dense.

Overproofed dough has fermented too long. The gluten structure weakens, gas pockets grow too large, and the dough loses elasticity. When scored and baked, it collapses instead of expanding.

The ideal proof is when the dough has increased by about 50–75%, feels light and airy, and springs back slowly when gently poked. The poke test: press a fingertip about half an inch into the dough. If it springs back slowly and leaves a slight indentation, it’s ready. If it doesn’t spring back, it’s overproofed. If it springs back immediately, it needs more time.

Proofing Condition	Visual & Tactile Signs	Solution
Underproofed	Dense feel, minimal rise, tight surface	Allow longer bulk fermentation or final proof
Overproofed	Saggy, dimples don’t rebound, weak structure	Reduce proof time, lower temperature, or strengthen gluten
Well-proofed	50–75% increase, soft but resilient, slight jiggle	Bake immediately

4. Shaping and Scoring: The Final Push for Oven Spring

Even with perfect fermentation, poor shaping can sabotage your loaf. The goal of shaping is to create surface tension that helps the dough hold its shape and expand upward rather than spreading out.

Common shaping mistakes include:

• Not pre-shaping (bench resting): Skipping this step prevents proper tension building.
• Over-handling: Excessive manipulation deflates gas and damages structure.
• Loose shaping: Failing to tighten the surface results in flat, pancake-like loaves.

For boules (round loaves), pull the edges toward the center and pinch to seal. Flip seam-side down and use cupped hands to rotate the dough against the counter, tightening the top skin. For batards (oval loaves), elongate gently and roll to create tension along the seam.

Scoring is equally important. Proper cuts allow controlled expansion in the oven. Shallow or hesitant slashes restrict oven spring. Deep, decisive cuts (about ½ inch deep) at a 30–45° angle help the loaf open dramatically.

Tip: Use a razor blade or lame for clean, precise scoring. Flour-dusted dough makes it easier to see your pattern.

5. Baking Environment: Heat, Steam, and Vessel Matters

Oven spring—the rapid rise in the first 15 minutes of baking—depends on three factors: heat, steam, and confinement.

Temperature: Bake at 450–475°F (230–245°C). Lower temperatures delay crust formation, but insufficient heat won’t trigger explosive expansion.

Steam: Moisture in the oven keeps the crust flexible longer, allowing the loaf to expand fully before setting. Without steam, the crust hardens too quickly, locking in a flat shape.

Baking vessel: Dutch ovens or combo cookers trap steam and radiate heat evenly. They provide the enclosed environment sourdough needs for maximum rise. Baking on a stone or sheet pan without containment often results in spreading.

If you’re not using a Dutch oven, create steam by placing a metal tray on the oven floor and pouring hot water into it just after loading the bread.

Step-by-Step Fix for Flat Loaves

1. Verify starter health: Feed and observe for 8 hours. It should double and be bubbly.
2. Adjust hydration: If dough feels slack, reduce water slightly (e.g., from 75% to 70% hydration).
3. Strengthen gluten: Add 3–4 sets of stretch-and-folds during bulk fermentation.
4. Control proof time: Use cooler temperatures (like refrigerated final proof) for better control.
5. Improve shaping: Practice surface tension techniques with moderate flour use.
6. Score confidently: Make bold, swift cuts before baking.
7. Bake hot with steam: Preheat Dutch oven for 45 minutes; bake covered for first 20 minutes.

Real Example: From Pancake to Perfect Boule

Sarah had been baking sourdough for months with no success. Her loaves were consistently flat, dense, and stuck to the banneton. She followed recipes exactly but saw no improvement. After reviewing her process, she realized three issues: her starter peaked at 6 hours but she used it at 12, meaning it was exhausted; she skipped stretch-and-folds; and she proofed her shaped loaf on the counter overnight in a warm kitchen.

She adjusted: fed her starter in the morning and used it at peak. Added four sets of folds during bulk fermentation. Switched to a cold final proof in the fridge for 12 hours. Tightened her shaping technique and scored deeply before baking in a preheated Dutch oven.

The next loaf rose two inches higher, had an open crumb, and cracked beautifully along the score. “I finally get it,” she said. “It wasn’t one thing—it was all the little things adding up.”

Essential Troubleshooting Checklist

Use this checklist to diagnose and correct flat sourdough:

• ✅ Is my starter doubling within 8 hours of feeding?
• ✅ Did I perform stretch-and-folds during bulk fermentation?
• ✅ Does my dough pass the windowpane test?
• ✅ Was the final proof timed correctly? (Poke test passed?)
• ✅ Did I create surface tension during shaping?
• ✅ Were scores deep and confident?
• ✅ Was the oven fully preheated with a baking vessel inside?
• ✅ Did I use steam or a closed pot for the first 20 minutes?

Frequently Asked Questions

Can I still bake overproofed dough?

You can, but expect a flat result. To salvage it, gently reshape the dough and refrigerate for 2–4 hours to firm it up and slow fermentation. This may recover some structure, but the best practice is prevention through timing and temperature control.

Why does my loaf spread after scoring?

This usually means the dough lacks strength or is overproofed. Strengthen the dough with more folds, reduce hydration slightly, or shorten proof time. Scoring too early—before the dough has developed resilience—can also cause immediate spreading.

Does flour type affect loaf height?

Yes. High-protein bread flour (12–14% protein) develops stronger gluten than all-purpose flour. Whole grain flours absorb more water but weaken gluten due to bran particles cutting the network. For taller loaves, use at least 80% bread flour and adjust water accordingly.

Final Thoughts: Consistency Breeds Success

Flat sourdough isn’t a failure—it’s feedback. Each loaf tells you something about your process. By isolating variables and making one adjustment at a time, you’ll gain confidence and consistency. Track your bakes: note starter timing, fold schedule, proof duration, and oven setup. Over time, patterns emerge, and so do better loaves.

Don’t aim for perfection on the first try. Aim for progress. With attention to starter health, gluten development, proofing, shaping, and baking conditions, you’ll move from flat disappointments to proudly tall, crackling sourdough.

💬 Have a flat loaf story or a breakthrough tip? Share your experience in the comments—your insight could help another baker rise above the same challenge.