Barm

Part of speech: noun

Pronunciation: /bɑːm/

Definitions

1. A frothy substance produced during fermentation, often from beer or bread; the yeast used in brewing or baking; a colloquial term for a type of froth or foam found in various contexts
2. A bubbling, frothy matter that emerges from the fermentation process in beverages like beer; a specific strain of yeast beneficial for leavening dough; informal reference to any light, airy foam seen in cooking or drinks
3. The light, spongy foam generated in brewing or baking processes as yeast ferments; a live culture used for raising dough and enhancing flavor; a casual expression for airy froth in culinary applications

Etymology: Barm is one of those English words whose meaning has narrowed while its older sense went quiet. The Old English "bearm" meant "lap" or "bosom," the part of the body that holds things, and it is the same word as the German "Barm," still used for lap or bosom. The yeast sense came from a separate root. Old English "beorma," and the related Middle Low German "barm," meant the frothy foam that rises on fermenting liquid, and that is what English speakers came to mean by it. The two words merged in English over time, which is why the same spelling can point to two unrelated origins. Brewers and bakers knew the foam as an ingredient, and the word stayed close to that practical use. A bread roll made with yeast, the "barmcake," gave a name to a regional bread, though whether the bread's name came from the yeast or from the Irish "bairín breac," a speckled loaf, is uncertain.

Synonyms: yeast, froth, foam