The Library / When it goes wrong

Gummy crumb has three quite different causes

Cut too early, underbaked, or high enzyme activity. They look similar and want opposite fixes.

Why

Cut too early and the starch hasn't finished setting: wait longer, change nothing else. Underbaked and the centre never reached temperature: bake longer or hotter. High enzyme activity, common with sprouted grain or a lot of rye, means starch is being broken into sugars faster than it can set. That one needs more acidity or less of the offending flour, and baking longer makes it worse.

Further down

Rye's answer to this is acidity itself: a properly sour rye ferment inhibits the amylase that would otherwise destroy the crumb. It's the clearest case in baking of sourness being functional rather than a flavour preference.

Words used here Crumb

Updated 7 October 2026