[AlanYx]

True! I also find it fascinating that the first recipe in the linked article (Wroclaw Trencher Bread) includes beer as an ingredient, which has had a popular revival recently as a bread hack to add maltiness/flavor. I've seen YouTubers complain that it isn't "authentic" somehow, but it looks like it really is more traditional than it seems!

[ch4s3]

Any premodern bread that wasn’t made like sourdough was made with beer barm. Bakeries and breweries were typical colocated. I’m not sure what was done in predominantly Muslim areas for yeast though, since they wouldn’t have had breweries.