Why Is My Sourdough Bread Gummy Inside Troubleshooting Guide For Home Bakers

Sourdough baking is both an art and a science. When done right, the result is a crusty, open-crumbed loaf with a tangy flavor that store-bought bread can’t match. But when something goes wrong—especially a gummy, dense interior—it can be frustrating. Many home bakers encounter this issue and assume their starter isn’t strong enough or that they’ve ruined the batch. The truth is, a gummy crumb has multiple potential causes, most of which are correctable with better technique, timing, and understanding of the fermentation process.

This guide breaks down the most common reasons behind gummy sourdough, offering clear explanations and actionable fixes so you can bake consistently great loaves at home.

Understanding What “Gummy” Means in Sourdough

When bakers describe their sourdough as “gummy,” they’re usually referring to a sticky, undercooked texture in the crumb. The bread may look baked on the outside but feels moist, chewy, or even slightly raw when sliced. This texture often develops shortly after cooling and worsens over time. It’s not just unpleasant—it indicates incomplete starch gelatinization or improper moisture management during baking.

Gumminess differs from denseness. A dense loaf might have poor oven spring or insufficient rise, but if it’s properly baked, the crumb will still be dry and airy. Gumminess, however, points to structural failure within the gluten-starch network, often due to underbaking, incorrect hydration, or fermentation issues.

Tip: Always let your sourdough cool completely—ideally 2–3 hours—before slicing. Cutting too soon traps steam, creating a false impression of gumminess.

Common Causes of Gummy Sourdough Crumb

1. Underbaking or Insufficient Oven Temperature

The most frequent culprit behind gummy sourdough is underbaking. Even if the crust looks deep brown and sounds hollow when tapped, the internal temperature might not have reached the necessary threshold to fully set the crumb. For sourdough, the internal temperature should reach at least 205°F (96°C) to ensure complete starch gelatinization and proper moisture evaporation.

Many home ovens run cooler than their dials suggest. Using an oven thermometer helps verify actual temperature. Additionally, baking without adequate steam or removing the lid too early (in Dutch oven baking) can prevent proper oven spring and heat penetration.

2. Overhydration Relative to Flour Type

High hydration doughs (above 75%) are popular for achieving open, airy crumb structures. However, using too much water—especially with low-protein flours like all-purpose or whole wheat—can overwhelm the gluten structure. When gluten can’t hold the excess moisture, the loaf collapses slightly during baking, trapping steam and leaving a sticky interior.

Different flours absorb water differently. Bread flour typically handles higher hydration better than all-purpose due to its higher protein content. Whole grain flours absorb more water initially but release it during baking if not managed correctly.

3. Underfermentation or Overfermentation

Fermentation is critical to developing both flavor and structure. Both under- and overfermentation lead to gummy results, though for different reasons.

• Underfermented dough lacks sufficient gas production and enzymatic activity. Starches aren’t fully converted into sugars, and gluten remains tight and unrelaxed. This leads to poor oven spring and uneven crumb structure, increasing the risk of trapped moisture.
• Overfermented dough breaks down the gluten network, weakening the dough’s ability to retain gas and support structure. As a result, the loaf deflates during baking, collapsing inward and creating dense, gummy patches.

4. Inadequate Gluten Development

Gluten is the scaffold that holds gas bubbles and supports the loaf during rise and bake. Without proper development—through mixing, folding, or autolyse—the dough cannot maintain its shape or allow even heat distribution. Poorly developed gluten also fails to trap moisture effectively, leading to localized wet spots in the crumb.

Signs of underdeveloped gluten include slack, sticky dough that doesn’t hold tension and tears easily during shaping.

5. Cooling and Storage Issues

Even a perfectly baked loaf can become gummy if sliced too early. Residual steam needs time to escape. Cutting before the loaf reaches room temperature forces moisture back into the crumb, making it appear underbaked.

Storing sourdough while still warm or in an airtight container too soon after baking traps humidity, accelerating sogginess and promoting mold growth.

“Temperature control and fermentation timing are non-negotiables in sourdough. A few hours too long or too short can ruin texture, no matter how good your starter is.” — Dr. Emily Tran, Food Scientist & Artisan Baker

Troubleshooting Checklist: Fixing Gummy Sourdough

Use this checklist to diagnose and correct the root cause of gummy crumb in your sourdough bread. Go through each item systematically after every bake until you identify the issue.

Checklist: How to Prevent Gummy Sourdough

1. ✅ Verify your oven temperature with a reliable thermometer
2. ✅ Use a digital probe thermometer to check internal loaf temp (target: 205–210°F / 96–99°C)
3. ✅ Adjust hydration based on flour type (e.g., reduce to 70% for AP flour)
4. ✅ Perform the windowpane test before bulk fermentation to confirm gluten development
5. ✅ Stick to recommended fermentation times and temperatures (typically 72–78°F / 22–26°C)
6. ✅ Allow full cooling (2–3 hours) before slicing
7. ✅ Bake with steam for first 20–25 minutes (use Dutch oven or steam pan)
8. ✅ Avoid overproofing—perform the poke test before baking

Step-by-Step Guide to Baking Non-Gummy Sourdough

Follow this detailed timeline to produce a well-structured, non-gummy sourdough loaf. This method emphasizes precision and observation over rigid schedules.

1. Feed your starter 8–12 hours before mixing
   Ensure it’s active, bubbly, and has doubled in volume. An inactive starter delays fermentation and weakens rise.
2. Mix dough using autolyse (30–60 minutes)
   Combine flour and water; let rest before adding salt and starter. This improves gluten formation and water absorption.
3. Knead or perform stretch-and-folds every 30 minutes during bulk fermentation (4x total)
   Build strength gradually. Watch for smooth, elastic dough that holds shape.
4. Bulk ferment at 75°F (24°C) for 3.5–5 hours
   Duration depends on ambient temperature and starter strength. Dough should rise ~50%, feel airy, and pass the jiggle test.
5. Shape tightly and use a well-floured banneton
   Surface tension helps maintain structure. Proof seam-side up to prevent spreading.
6. Final proof: 1–2 hours at room temp or overnight in fridge
   Cold proofing enhances flavor and reduces overfermentation risk. Perform the finger poke test: if indentation slowly springs back, it’s ready.
7. Preheat oven and vessel (Dutch oven) for 45–60 minutes at 450°F (230°C)
   Thermal mass ensures immediate oven spring and consistent heat transfer.
8. Bake covered for 20 minutes, then uncovered for 20–25 minutes
   Covering traps steam for expansion; uncovering allows crust to harden and moisture to escape.
9. Check internal temperature: must reach at least 205°F (96°C)
   If below target, return to oven in 5-minute increments.
10. Cool completely on a wire rack (2–3 hours)
    Do not skip this step. Premature slicing is a leading cause of perceived gumminess.

Hydration Guidelines by Flour Type

Using the right hydration level for your flour is essential to avoid gummy textures. The table below provides safe starting points for beginners.

Flour Type	Recommended Hydration	Notes
All-Purpose Flour	65–70%	Lower protein content; struggles with high hydration. Ideal for beginners.
Bread Flour	70–78%	Higher gluten strength allows for more water and better oven spring.
Whole Wheat Flour	70–75%	Absorbs more water but ferments faster. Mix with white flour for stability.
Spelt or Rye Flour	60–68%	Weak gluten structure; requires shorter fermentation and lower hydration.
Blends (e.g., 90% white + 10% whole)	72–75%	Balances flavor and strength. Great for intermediate bakers.

Tip: If adjusting hydration, change by only 2–3% per bake. Small changes make big differences in texture.

Real Example: From Gummy Loaf to Bakery-Quality Bread

Sarah, a home baker in Portland, struggled for months with dense, gummy sourdough. Her starter was active, she followed recipes closely, but her loaves never turned out right. She used 78% hydration with all-purpose flour, bulk fermented for 5 hours at 80°F (27°C), and baked in a preheated Dutch oven.

After tracking her process, she realized three key mistakes:

• Her kitchen was too warm, causing overfermentation.
• All-purpose flour couldn’t handle 78% hydration.
• She was cutting the bread after only 45 minutes of cooling.

She adjusted her routine: lowered hydration to 68%, moved fermentation to a cooler part of the house (72°F), reduced bulk time to 4 hours, and waited 3 hours before slicing. Her next loaf had a light, even crumb with no gumminess. “I didn’t need a new recipe,” she said. “I needed to understand what each variable actually did.”

Frequently Asked Questions

Can I fix a gummy loaf after baking?

No, once a loaf is baked and cooled, the texture cannot be reversed. However, you can repurpose it: toast slices thoroughly, use in breadcrumbs, or make sourdough croutons. The heat will drive off residual moisture and improve texture.

Does a stronger starter prevent gumminess?

Not directly. While a healthy starter ensures proper fermentation, gumminess is more often caused by hydration, baking temperature, or timing errors. A strong starter won’t compensate for underbaking or poor gluten development.

Why does my sourdough taste sour but still have a gummy center?

Acidity comes from lactic and acetic acid produced during fermentation, which doesn’t correlate with structural integrity. You can have a very sour but poorly baked loaf. Flavor and texture are influenced by different factors—proofing conditions affect taste; baking and dough handling affect texture.

Conclusion: Master Your Process, Not Just the Recipe

Gummy sourdough isn’t a dead end—it’s feedback. Each loaf tells you something about your technique, environment, and ingredients. By paying attention to hydration, fermentation, baking temperature, and cooling time, you gain control over the variables that matter most.

Don’t chase trends like ultra-high hydration unless your skills and flour choice support it. Start simple, measure outcomes, and adjust one variable at a time. With patience and observation, you’ll move beyond gummy failures to consistent, bakery-quality results.

💬 Have a sourdough success story or a persistent issue? Share your experience in the comments—your insight could help another baker crack the code to perfect crumb!