Reading a crumb: dense, tight, open, gummy and everything between

A tin loaf for sandwiches is SUPPOSED to have a fine, even, closed crumb. An open irregular crumb makes a bad sandwich and leaks. A baguette is supposed to be open; a milk bread is supposed to be soft and close; a rye is supposed to be dense by any wheat standard.\n\nA large share of crumb questions are really comparisons against a photograph of a different bread. Before diagnosing anything, it is worth asking what this bread’s crumb is meant to be, which BakeHQ records on the product pages for exactly this reason.\n\nThe rest of this guide assumes the crumb genuinely is not what that bread should have.

TIGHT OR DENSE. Small, uniform cells; the loaf is heavy for its size. The gas was never made, was never held, or was pushed out. This is a fermentation, development or shaping question, and the discriminating observations are on the dense-crumb model.\n\nGUMMY OR DOUGHY. The crumb is damp and clings to the knife, sometimes as a compressed layer near the base. This is almost never a fermentation problem — it is starch that has not finished setting, or a bread cut before it had cooled. A rye or high-enzyme flour makes it much more likely.\n\nCRUMBLY. It falls apart when sliced. Something is missing structurally: not enough gluten built, not enough water, or a gluten-free system whose binder is not doing its job. Note that this is the opposite failure from gummy and the two are regularly confused, because both are described as “not cooked properly”.\n\nIRREGULAR — GIANT HOLES, OR TUNNELS UNDER THE CRUST. Large voids in an otherwise ordinary crumb usually come from trapped gas rather than good fermentation: a shaping fold that sealed in a pocket, or a skin that formed during proving. A single cavern under the top crust is a shaping fault, not a badge.

“HIGHER HYDRATION MAKES AN OPEN CRUMB.” It permits one; it does not produce one. A wetter dough is more extensible, so cells can expand further before the walls fail — but a wet dough that has been under-developed or degassed at shaping gives a flat, close loaf, and a great many people who raise hydration in pursuit of holes get exactly that. Hydration removes a constraint; it does not supply the gas or the structure.\n\n“MORE FOLDS MAKE A MORE OPEN CRUMB.” Folds build strength, and strength is necessary. They also degas, and degassing is the direct enemy of the thing being pursued. Which effect dominates depends entirely on where the dough was starting from: on an under-strength dough more folds help, and on a dough that already holds its shape they make the crumb tighter. There is no direction that is right in general.\n\n“BIG HOLES MEAN GOOD FERMENTATION.” Sometimes, and the counterexample is common enough to be worth naming: a single large cavity under the crust is a trapped pocket from shaping, and it appears on loaves that were fermented badly as readily as on ones that were fermented well. An evenly open crumb and one big hole are different observations and mean different things.\n\nWhat an open crumb actually requires is all three of enough gas, a network extensible enough to be inflated by it, and handling that did not push the gas out. Hydration only ever addresses the second.

A compressed band along the bottom of an otherwise reasonable loaf is a specific and common observation, and it usually has one of two explanations.\n\nIf it is damp as well as dense, it is the gummy case: the base sat where heat arrived last, or the loaf was cut before it finished setting and the moisture settled.\n\nIf it is dry and dense, the dough was heavy enough to compress itself under its own weight during proving, which points at a network too weak or a hydration too high for the shape it was asked to hold.\n\nThe difference is whether it is wet, which takes a second to check and rules out half the possibilities.