Reading Your Sourdough Crumb: What It Tells You

Every slice of sourdough tells a story about how it was made. Learning to read your crumb — the interior structure of your bread — provides feedback that helps you refine your process and improve with every bake.

Open vs Tight Crumb

An open crumb with large, irregular holes indicates strong fermentation, good gluten development, and gentle handling. It is typical of high-hydration artisan sourdough and results from abundant gas production trapped by a well-developed gluten network.

A tight, even crumb with small uniform holes is not necessarily a flaw — it is appropriate for sandwich bread, lower-hydration loaves, and some whole grain breads. The key question is whether your crumb matches your intention.

What Dense Spots Mean

Dense areas near the bottom of the loaf (often called a "flying crust" with a gap above) indicate the dough was under-proofed or not shaped with enough tension. The gas rises during baking while the dense base cannot expand.

Dense spots in the center usually mean under-fermentation during bulk. The exterior ferments faster (warmer) while the interior lags behind. Better dough temperature management through stretch and folds distributes fermentation more evenly.

Large Holes and Tunneling

A few very large holes while the rest of the crumb is tight suggests trapped air during shaping rather than fermentation. Pressing air out gently during pre-shaping helps distribute gas more evenly.

Tunneling — large elongated holes running horizontally — often results from under-developed gluten that cannot contain expanding gas. The gas finds the weakest path and creates channels. More stretch and folds or a longer autolyse helps.

Gummy or Wet Crumb

A gummy, sticky interior that clings to the knife indicates the bread was either under-baked or cut before it finished cooling. Internal temperature should reach 205-210°F. Wait at least 2 hours before slicing.

Persistent gumminess despite proper baking and cooling points to excessive enzyme activity, over-hydration, or an extremely high extraction flour. Reducing hydration by 3-5% or switching flour brands may resolve the issue.

The Essential Points

The techniques and knowledge shared here build the foundation for consistent, rewarding results. Whether you are just starting out or refining your craft, focusing on fundamentals always pays dividends.

Start with what interests you most, practice deliberately, and do not be afraid to experiment. Every batch teaches you something new, and the journey of improvement is what makes this pursuit so engaging.