An Etymological Dictionary of the German Language/Annotated/Bärme

Bärme, feminine, ‘yeast,’ borrowed from the equivalent Low German barme, masculine, which corresponds to Anglo-Saxon beorma and English barm. Latin fermentum (if it does not belong to formus, Greek θερμός, ‘warm’) is perhaps akin to it. Teutonic b, Latin f, are Aryan bh.