Reading the Crumb: What Your Bread Is Trying to Tell You

Cut a loaf in half and you are looking at a record of its whole life: how strong the gluten was, how long it fermented, how it was shaped and how hot the oven was. Learning to read that record is the fastest way to improve.

Four crumbs and what they mean

Big holes at the top, dense at the bottom

Under-fermented. The yeast did not have time to inflate the whole dough, so gas collected under the crust in a few tunnels. Extend the bulk ferment by 30–60 minutes or keep the dough warmer.

Even, tight, cottony holes

Low hydration or over-handled. Perfect for sandwiches. If you wanted more openness, add 5% water and be gentler when shaping.

Flat loaf, large irregular holes, gummy

Over-fermented. The gluten network gave out. Shorten the bulk, or retard sooner.

Open, glossy, even-ish holes throughout

Well fermented. Take a photo. Write down exactly what you did. You will not manage it again for three weeks.

The crumb is not a goal. It is feedback.

Keep a bake log

I keep a plain text file. One line per bake, with the numbers that actually change from week to week:

date        flour           hyd  levain  bulk   temp  retard  notes
2026-09-14  bread+10%ww     75%  20%     5h15   24C   14h     good ear, tight base
2026-09-21  bread+10%ww     75%  20%     6h00   23C   15h     best yet
2026-09-27  bread+20%rye    78%  20%     4h30   26C   12h     over: flat, gummy

After a dozen lines, patterns jump out that you would never notice from memory: the kitchen got two degrees warmer in September and every bake since has been a little over-proofed.