Why Is My Sourdough Bread Gummy Inside Common Mistakes And How To Avoid Them

Sourdough bread is celebrated for its complex flavor, chewy crust, and airy, open crumb. But nothing is more disappointing than slicing into a loaf only to find a dense, sticky, gummy interior. This issue is surprisingly common—even among experienced home bakers—and often stems from subtle missteps in the baking process. The good news? Most causes are easily corrected with the right knowledge. Understanding why your sourdough turns out gummy can transform your baking from inconsistent to reliable.

A gummy crumb typically means the starches in the flour haven’t fully set or that excess moisture remains trapped in the loaf. While it might look baked on the outside, the internal structure hasn’t matured properly. Fixing this requires attention to fermentation, hydration, shaping, oven spring, and cooling. Let’s break down the most frequent culprits and how to address them.

Underfermentation: The Silent Crumb Killer

One of the leading reasons for a gummy sourdough interior is underfermentation. When dough hasn’t fermented long enough, the yeast and bacteria in your starter haven’t had sufficient time to break down the starches and sugars in the flour. This incomplete conversion leaves behind unconverted starch that traps water, resulting in a sticky, glue-like texture after baking.

Signs of underfermentation include:

• Dense, compact crumb with few large holes
• Lack of noticeable sour aroma
• Dough feels tight and resists stretching
• Minimal rise during proofing

Fermentation isn’t just about time—it’s about temperature, starter strength, and dough maturity. A cold kitchen slows fermentation dramatically. If you’re following a recipe that assumes an 8-hour bulk ferment at 75°F (24°C), but your kitchen is only 65°F (18°C), your dough may need 10–12 hours instead.

Tip: Use the \"poke test\" to assess fermentation: gently press your finger into the dough. If it springs back slowly and leaves a slight indentation, it’s ready. If it snaps back quickly, it needs more time.

Overhydration Without Proper Gluten Development

High hydration doughs—common in artisan sourdough recipes—can produce beautiful open crumb structures. However, too much water without sufficient gluten development leads to a weak dough structure that collapses during baking, trapping steam and moisture inside.

When gluten networks aren’t strong enough to hold gas bubbles, the dough spreads instead of rising vertically. This results in poor oven spring and a dense, gummy center. High hydration also increases the risk of underbaking because more water must evaporate during baking.

To manage hydration effectively:

1. Use autolyse: Mix flour and water and let rest for 30–60 minutes before adding salt and starter. This improves gluten formation.
2. Perform regular stretch and folds during bulk fermentation to build strength.
3. Adjust hydration based on flour type—whole grain flours absorb more water than white flour.

Flour Type	Recommended Hydration Range	Notes
All-Purpose White	65%–75%	Easier to handle; ideal for beginners
Bread Flour	70%–78%	Higher protein supports better structure
Whole Wheat	75%–85%	Requires longer autolyse and more folds
Rye Flour	80%–90%	Very low gluten; best used in blends

Inadequate Oven Spring and Underbaking

Oven spring—the rapid expansion of dough in the first 15–20 minutes of baking—is critical for proper crumb structure. Poor oven spring often leads to a compact, gummy interior because gases don’t expand sufficiently to create air pockets, and moisture has nowhere to escape.

Common causes of poor oven spring include:

• Underproofed dough: Too dense to expand
• Overproofed dough: Structure collapses under heat
• Insufficient oven temperature: Needs at least 450°F (230°C)
• Lack of steam: Steam keeps the crust flexible early in baking, allowing maximum expansion

Even if your loaf looks golden brown, it may still be underbaked internally. Sourdough needs both external color and internal temperature to be correct. A fully baked loaf should reach an internal temperature of 205–210°F (96–99°C). Anything below 200°F (93°C) risks a gummy center.

“Many home bakers pull their bread out too early, mistaking crust color for doneness. Always use a thermometer.” — Daniel Leader, author of *Local Breads* and founder of Bread Alone Bakery

The Cooling Mistake Everyone Makes

Perhaps the most overlooked factor in gummy sourdough is premature slicing. Cutting into a hot loaf seems tempting, but doing so releases trapped steam that’s still setting the crumb. When you slice too soon, moisture condenses back into the interior, creating a sticky, pasty texture.

Starch retrogradation—the process where gelatinized starch molecules reorganize and firm up—continues for up to two hours after the bread leaves the oven. Interrupting this process by cutting early prevents the crumb from fully stabilizing.

Tip: Set a timer for at least 2 hours before slicing. For larger loaves like miche or rye-based breads, wait 3–4 hours.

Step-by-Step Guide to Prevent Gummy Sourdough

Follow this sequence to ensure a well-baked, non-gummy loaf every time:

1. Feed your starter 8–12 hours before mixing: Ensure it peaks within 4–6 hours and floats in water.
2. Autolyse flour and water for 30–60 minutes: This jumpstarts gluten development.
3. Perform 4–6 sets of stretch and folds during bulk fermentation, spaced 30 minutes apart.
4. Proof until ripe: Use the poke test and look for visible bubbles near the surface.
5. Preheat oven and baking vessel for 1 hour at 450–475°F (230–245°C).
6. Bake with steam for the first 20 minutes (use a Dutch oven or add ice cubes to a tray).
7. Finish baking uncovered for another 20–25 minutes until deeply colored.
8. Check internal temperature: Must reach at least 205°F (96°C).
9. Cool completely on a wire rack: Wait a minimum of 2 hours before slicing.

Real Example: Sarah’s Sourdough Struggle

Sarah had been baking sourdough for six months, consistently getting flat, gummy loaves despite following online recipes to the letter. She used bread flour at 75% hydration, did stretch and folds, and baked in a Dutch oven. Yet her crumb remained sticky.

After reviewing her process, she realized two issues: First, she was baking after only 8 hours of bulk fermentation in a 68°F (20°C) kitchen—far too short. Second, she was slicing her bread within 30 minutes of removing it from the oven.

She adjusted her timeline to a 12-hour bulk ferment and waited 3 hours before cutting. The difference was dramatic: her next loaf had an open crumb, crisp crust, and no gumminess. The change wasn’t in ingredients—it was in patience and timing.

Do’s and Don’ts of Sourdough Baking

Do	Don't
Use a digital scale for accurate measurements	Measure flour by volume (cups)
Let dough pass the windowpane test	Assume mixing equals gluten development
Bake to internal temp of 205°F+	Remove bread when crust looks done
Cool loaf completely before slicing	Cut into hot bread “to check”
Preheat baking vessel thoroughly	Place dough in a cold Dutch oven

Frequently Asked Questions

Can I rebake a gummy sourdough loaf?

No—once a loaf is cooled, rebaking will dry out the exterior without fixing the internal structure. However, if caught immediately after baking, you can return it to a 350°F (175°C) oven for 10–15 minutes to drive out excess moisture. Always check the internal temperature first.

Does using whole grain flour cause gumminess?

Not inherently, but whole grains absorb more water and have less gluten, which can lead to denser crumb if not handled properly. Increase fermentation time and consider blending with bread flour to improve structure.

Why does my sourdough taste alcoholic and feel gummy?

This usually indicates overfermentation. While underfermentation causes gumminess, overfermentation breaks down gluten too much, causing collapse and off-flavors. Balance your time, temperature, and starter ratio to hit the sweet spot.

Essential Checklist for Non-Gummy Sourdough

• ✅ Starter is active and passes the float test
• ✅ Dough shows signs of fermentation (bubbles, domed surface)
• ✅ Gluten is well-developed (passes windowpane test)
• ✅ Bulk fermentation matches ambient temperature
• ✅ Proofing ends just before dough starts to deflate
• ✅ Oven and vessel preheated for at least 60 minutes
• ✅ Baked with steam for first 20 minutes
• ✅ Internal temperature reaches 205–210°F (96–99°C)
• ✅ Loaf cools completely before slicing (minimum 2 hours)

Final Thoughts: Mastery Through Observation

Perfect sourdough isn’t about rigid adherence to recipes—it’s about understanding the behavior of dough and adjusting in real time. Gumminess is not a failure, but feedback. Each loaf teaches you something about your environment, ingredients, and technique.

The most skilled bakers don’t rely solely on timers or temperatures. They watch for visual cues, feel the elasticity of the dough, and trust the process. With consistent practice and attention to detail, you’ll move beyond gummy interiors to achieve loaves with crisp crusts, tangy flavor, and tender, airy crumb.

💬 Have you cracked the code on gummy sourdough? Share your breakthrough moment or ask a question in the comments—your experience could help another baker get one step closer to the perfect loaf.