Why Is My Sourdough Bread Gummy Inside And How To Fix The Crumb Structure

Sourdough bread should be a celebration of texture and flavor—crispy crust, open crumb, and a tender, chewy interior with just the right amount of tang. But when you slice into your loaf only to find a dense, sticky, gummy center, it’s not just disappointing; it can feel like a betrayal after hours of careful fermentation and baking. The good news? A gummy crumb is rarely a sign that your entire process has failed. More often, it's a symptom of one or two specific missteps in your sourdough journey—ones that are entirely correctable.

Understanding what causes gumminess means understanding how bread sets during baking. Gluten forms the structural web, starch gelatinizes to provide firmness, and moisture must escape at the right rate. When any part of this system breaks down, the result is a wet, underdeveloped crumb that sticks to the knife and collapses when sliced. Let’s explore the root causes and practical fixes so you can consistently bake loaves with strong, airy crumb structure.

What Causes Gummy Crumb in Sourdough?

A gummy interior typically stems from incomplete starch gelatinization or excess residual moisture trapped in the crumb. While several factors contribute, they usually fall into four main categories: underbaking, improper hydration, poor gluten development, or premature slicing.

• Underbaking: If the internal temperature doesn’t reach at least 205°F (96°C), starches haven’t fully set, leaving pockets of uncooked dough.
• Excessive hydration: Too much water overwhelms gluten’s ability to hold structure, leading to collapse and moisture retention.
• Weaker gluten network: Inadequate kneading, under-fermentation, or using low-protein flour prevents proper gas retention.
• Cooling too quickly or slicing too soon: Heat and steam need time to escape evenly. Cutting early traps moisture inside.

Tip: Always use an instant-read thermometer to verify doneness. Aim for 205–210°F (96–99°C) in the center of the loaf.

How Baking Science Affects Crumb Structure

Bread isn't just flour, water, salt, and time—it’s chemistry in motion. During baking, three critical transformations occur: oven spring, starch gelatinization, and protein coagulation.

Oven spring happens in the first 15–20 minutes, fueled by CO₂ expansion and steam. As heat increases, gluten strands tighten and set, while starch granules absorb water and swell until they burst, releasing amylose and amylopectin. This gelatinized starch solidifies upon cooling, giving bread its final structure. If this process is interrupted—by insufficient heat, inadequate steam, or early removal from the oven—the starch fails to fully gelatinize, resulting in a soft, sticky matrix.

Moisture plays a dual role. Adequate hydration supports enzymatic activity and extensibility, but too much without compensating strength leads to collapse. High-hydration doughs (above 78%) demand excellent gluten development and precise baking conditions to avoid gumminess.

“Starch gelatinization is non-negotiable. You can have perfect fermentation, but if your bread doesn’t reach full gelatinization, you’ll end up with a gummy mess.” — Dr. Richard Coppelia, Food Scientist & Artisan Bread Researcher

Step-by-Step Guide to Fixing Gummy Sourdough

Follow this systematic approach to diagnose and resolve the issue based on your current process.

1. Verify Your Oven Temperature
   Use an independent oven thermometer. Many home ovens run cooler than indicated, especially when preheating with a Dutch oven. Underheated ovens delay crust formation and slow internal cooking.
2. Extend Baking Time
   Bake covered for 20–25 minutes to trap steam, then uncover and continue baking 20–30 minutes more. For stubborn gumminess, extend uncovered baking by 5–10 minutes, watching for deep golden-brown color.
3. Check Internal Temperature
   Insert a digital probe into the center. It must read at least 205°F (96°C). If below, return to oven even if the crust looks done.
4. Adjust Hydration Gradually
   If using 80%+ hydration, reduce by 5% and strengthen mixing or folding technique. High hydration demands skill—don’t rush into 85% before mastering 75%.
5. Improve Gluten Development
   Perform 4–6 coil folds during bulk fermentation. Alternatively, mix dough slightly longer during autolyse or use slap-and-fold if hand-kneading.
6. Ensure Full Fermentation
   Underproofed dough lacks gas retention; overproofed dough collapses. Look for domed surface, jiggly texture, and risen volume (50–75% increase).
7. Cool Completely Before Slicing
   Wait at least 2 hours for large boules. Residual steam needs time to redistribute and condense, allowing starch to fully set.

Do’s and Don’ts for Achieving Open, Non-Gummy Crumb

Do	Don’t
Use bread flour (12–13% protein) for better gluten strength	Use all-purpose flour without adjusting hydration or handling
Preheat Dutch oven for 45–60 minutes	Place dough in a cold or inadequately heated vessel
Score deeply (½ inch) to allow controlled expansion	Make shallow cuts that restrict oven spring
Allow full cooling time before slicing	Cut into hot bread out of impatience
Track variables: time, temp, hydration, flour type	Change multiple factors at once without logging results

Tip: Rotate your loaf halfway through uncovered baking to counteract oven hot spots that cause uneven cooking.

Real Example: From Gummy Loaf to Bakery-Quality Crumb

Jenna, a home baker in Portland, had been struggling for months with dense, gummy sourdough. Her starter was active, she followed recipes closely, and her crust looked perfect—but every slice revealed a wet, gluey center. She assumed she needed higher hydration for “better holes,” so she increased water from 75% to 82%, worsening the problem.

After reviewing her process, two issues emerged: her oven ran 25°F cooler than displayed, and she was slicing within 45 minutes of pulling the loaf out. She began using an oven thermometer, extended uncovered baking by 12 minutes, and waited two full hours before cutting. The next loaf showed dramatic improvement—light, airy crumb with no stickiness. She later reduced hydration to 78% and added extra coil folds, achieving consistent results. Her key insight? “I thought more moisture meant more openness, but really, I needed more structure.”

Checklist: Fix Gummy Sourdough in 7 Steps

• ✅ Confirm oven temperature with a separate thermometer
• ✅ Bake until internal temp reaches 205–210°F (96–99°C)
• ✅ Cool bread completely (minimum 2 hours) before slicing
• ✅ Reduce hydration if above 78% without advanced shaping skills
• ✅ Perform adequate coil folds or stretch-and-folds for gluten strength
• ✅ Score deeply and confidently before baking
• ✅ Keep a baking journal to track changes and outcomes

Frequently Asked Questions

Can I rebake a gummy sourdough loaf?

Yes, but only if caught immediately. If the loaf is still warm and gummy due to underbaking, return it to a 375°F (190°C) oven, uncovered, for 10–15 minutes. Check internal temperature again. Do not attempt this with cooled bread, as it will dry out the crust without fixing the crumb.

Does using whole wheat flour cause gumminess?

Not inherently, but whole wheat absorbs more water and contains less gluten-forming protein. If substituting more than 20% whole grain, increase hydration slightly and expect denser crumb. To prevent gumminess, ensure longer autolyse and thorough mixing to hydrate bran particles.

Is a gummy crumb ever safe to eat?

If the bread smells normal, has risen properly, and shows no mold, it’s safe—but unpleasant. Gumminess is a textural flaw, not a safety issue. However, persistent sogginess may encourage microbial growth over time, so consume quickly or freeze.

Mastering Crumb Structure Through Consistency

The path to flawless sourdough isn’t about perfection on the first try—it’s about precision, observation, and adjustment. Each variable in your bake interacts with the others: a cooler kitchen slows fermentation, altering proofing time; a new flour brand absorbs water differently; even humidity affects dough behavior. The most successful bakers aren’t those with the fanciest equipment, but those who pay attention and respond intelligently.

When troubleshooting gumminess, isolate one variable at a time. Did you change flour? Adjust hydration? Was your starter peak ripe? Answering these questions systematically turns frustration into learning. Over time, you’ll develop intuition—knowing by sight and touch when dough is ready, when to extend baking, and when to wait just a little longer before slicing.

Remember, even professional bakers produce off-loaves. What separates them is their ability to diagnose and adapt. A gummy interior isn’t failure—it’s feedback.

💬 Have a gummy loaf story or a breakthrough tip? Share your experience in the comments—your insight could help another baker crack the code to perfect crumb structure.