Troubleshooting: Large Irregular Holes in Sourdough Crumb

Why does my sourdough loaf have large, irregular holes? Practical diagnosis, fixes, and prevention so you get an even crumb without losing open texture.

Quick Diagnosis

What kind of large holes are you seeing?

A few very large pockets (one or two big tunnels) Many uneven medium-to-large holes with thin walls Large holes concentrated near the bottom Open but wildly irregular crumb overall

Causes & Solutions

Insufficient degassing / gentle shaping

very common

Symptoms:

  • • One or two large gas pockets
  • • Loaf looks lopsided after scoring
  • • Thin walls around holes

Why does this happen?

If large bubbles are not gently redistributed before final shaping the gas concentrates into a few pockets that expand in the oven. Surface tension and even lamination during shaping control gas distribution [1].

🚨 Immediate Fix:

For the current dough: reshape with firmer, controlled degassing — gently press to deflate the largest bubbles, then create surface tension with a tighter seam. Use a dough scraper to lift and fold if needed.

📅 Long-term Fix:

Practice a shaping routine that balances degassing and tension: coil or letter folds during bulk to create an even network, then pre-shape, bench rest, final shape with consistent tension [1].

🧪 Test:

During final shaping, feel for large air pockets and deflate selectively; the dough should feel near-uniform with no big lumps.

Over-hydration without sufficient gluten development

common

Symptoms:

  • • Very wet, slack dough
  • • Thin cell walls and collapse near holes
  • • Dough hard to handle

Why does this happen?

High-hydration dough creates large gas cells easily, but without enough gluten structure those cells coalesce into irregular holes. Strength comes from gluten development (stretch-and-fold, autolyse timing) [1][2].

🚨 Immediate Fix:

Use stronger handling: more stretch-and-folds during bulk fermentation and shorter bench rest before shaping. Use a bench scraper to help shape wet dough.

📅 Long-term Fix:

Adjust hydration down in 1–2% increments until you can develop a cohesive gluten network, or increase gluten strength with longer autolyse or stronger flour (higher protein).

🧪 Test:

Windowpane test: thin membrane should stretch without tearing. If it tears easily the gluten needs more work.

Poor shaping technique or under-tensioned loaf

very common

Symptoms:

  • • Large holes near the bottom or one side
  • • Loaf collapses in oven on that side
  • • Crumb has uneven distribution of cells

Why does this happen?

Shaping creates surface tension that supports oven spring. Poor seam placement or weak tension lets large bubbles migrate downward and create pockets near the bottom during final proof or oven spring [1][2].

🚨 Immediate Fix:

Before baking, turn loaf seam-side-up and gently pat to redistribute. Use a banneton proofing basket for more uniform support during final proof.

📅 Long-term Fix:

Learn consistent shaping that seals seams and builds tension: tight coil or batard shaping with a final roll that tightens the surface.

🧪 Test:

After shaping the loaf should hold its shape on the bench and have a taut surface; if it spreads, tension is insufficient.

Under-fermented bulk or uneven fermentation (big bubbles formed late)

common

Symptoms:

  • • Large gas cells that appear suddenly late in bulk or during final proof
  • • Loaf shows uneven fermentation signs (dense in some places, very open in others)

Why does this happen?

If fermentation is uneven, some areas produce gas earlier and others later; late large bubbles haven’t been integrated into the gluten matrix and become oversized in the oven. Proper bulk time, folding schedule, and temperature control create uniform gas production [1][2].

🚨 Immediate Fix:

If still in final proof, very gently press the largest bubbles out and reshape briefly. For future bakes, add an extra round of folds earlier in bulk.

📅 Long-term Fix:

Standardize bulk fermentation: track dough temperature with an instant-read thermometer, perform regular folds (every 30–60 minutes) until dough shows even rise and windowpane development.

🧪 Test:

Bulk should show even increase in volume, smooth and domed surface, and visible small bubbles throughout when you perform folds.

Over-proofing followed by sudden oven spring

medium

Symptoms:

  • • Crust thin with very large internal holes
  • • Loaf smells strongly fermented
  • • Poor oven spring control

Why does this happen?

An over-proofed dough has weakened gluten; when exposed to oven heat residual steam and gas can cause weak points to blow out into large holes rather than controlled expansion [1].

🚨 Immediate Fix:

If you suspect over-proofing, score shallowly to control where steam escapes and accept a flatter loaf; for next time retime proofs or chill final proof to slow fermentation.

📅 Long-term Fix:

Shorten final proof or proof cooler; use the poke test to judge readiness (dough should slowly spring back), and consider cold retard in a clear straight-sided container or banneton to firm the dough before baking.

🧪 Test:

Poke test: over-proofed dough leaves a deep dent that does not recover.

Shaping air trapped under the loaf (seam traps bubble)

medium

Symptoms:

  • • Large bubble directly under the seam or top crust
  • • Score didn't open as expected

Why does this happen?

If shaping traps an air pocket under the seam, it will expand in the oven into a large hole. Proper seam sealing and inspection before final proof prevent this [2].

🚨 Immediate Fix:

Before baking, flip the loaf and press gently on suspected spots to release trapped air, reseal seam if possible. Score to direct expansion toward the blade.

📅 Long-term Fix:

During shaping, cup with hands and roll away from the seam to push air out; inspect the underside for lumps before final proof.

🧪 Test:

After pre-shape and final shape, run your fingers along the seam to feel for trapped pockets; smoothing indicates good sealing.

🆘 Emergency Fixes

You see a very large bubble just before loading the oven

Solution: Quickly poke it with a clean needle or bread lame to deflate, then score and bake immediately.

Success chance: good

Loaf already baked with one huge tunnel

Solution: Slice near the tunnel, use cut pieces for toasting or sandwiches; repurpose dense portions into breadcrumbs or croutons.

Success chance: n/a (culinary salvage)

Multiple large holes from over-proofing

Solution: For future: cold retard in fridge for 8–12 hours to firm dough before baking; for current loaves accept flatter shape and adjust expectations.

Success chance: good for flavor, variable for oven spring

Prevention

  • ☐ Develop gluten: autolyse (20–60 min) + dedicated stretch-and-folds during bulk [1]
  • ☐ Track dough temperature (target ~24–26°C / 75–78°F) with an instant-read thermometer to standardize fermentation
  • ☐ Degas selectively before final shaping; remove large bubbles by hand
  • ☐ Create surface tension during final shape and check seam; use a banneton proofing basket for support
  • ☐ Adjust hydration to what your flour and technique can handle; lower hydration slightly if structure is weak
  • ☐ Use consistent folding schedule to encourage even gas distribution and avoid late-forming big bubbles [2]

Sources

  1. [1]
    The Perfect Loaf – The Perfect Loaf – Link
  2. [2]
    Plötzblog – Plötzblog – Link