The word itself seems to be derived from *olъ 'fermented drink' (early borrowing from Old High German), and is attested in Old Church Slavonic and Old Russian as well as modern Bulgarian.
Ok thanks. I often noticed mentionings of Bulgarian alovina becouse here among Slovenes at least among Carinthians a brewing tradition of beer called ol, vuv, uew, etc, etc. also survived up to 19th century. Its not known about this by most folks nowdays. Our ol was brewed from various grains but most oftenly oat, wheat, barley or even buckwheat (which technically isnt grain). I managed to find some pretty old and detailed article about brewing process.
I won't tell all secrets (muahahah) but wort was filtered with juniper twigs + juniper was main spice used in brewing besides hops. Actually i read often hops weren't even used or were in low quantaties. I asked about process of Bulgarian alovina becouse i want to see how close your brewing technique was to ours. Technically in its broader sense Kvass is sort of very "primitve" form of beer but still i believe Bulgar alovina must have been more akin to beer brewing. I could be wrong ofc.
I would also argue that word ol is not Germanic (or solely Germanic) in origin at all. Acording to several pretty detailed articles about it i read that it is possibly PIE in origin or from caucasious. There were couple of those authors and at least one noted that idea that Slavic olovina, etc. must neccesarly steem from Germanic languages is far fetched. Indeed word ol is described in Slovene dictionary as old Slavic word for beer and Czech placename Olomouc is also said to descent from old Slavic term for beer. Anyways this word ol was sole word for beer in Slovene dictionaries before late 19th century. Besides ol and its various dialectical derivations we only had adoption of words per, pir from Middle High German.