Can confirm. Per the (paywalled) Oxford English Dictionary [0]: 'barm' is The froth that forms on the top of fermenting malt liquors, which is used to leaven bread, and to cause fermentation in other liquors; yeast, leaven. OR The froth or foam on the surface of beer OR English regional (chiefly Lancashire). A soft round bread roll, a barm cake.
[0] https://www.oed.com/dictionary/barm_n2?tab=meaning_and_use#2...