Although we have learned that it is forbidden to drink non-Jewish wine, both because of concern lest it be libated to idol worship and because the Sages want to discourage social intercourse between Jews and pagans, we do not find in the Mishnah or baraitot any prohibition against drinking non-Jewish beer. The Gemara on today’s daf (=page) nevertheless asks why non-Jewish beer is forbidden, and it appears that this was a late tradition.
Two reasons are offered by the Gemara to prohibit drinking non-Jewish beer – Rami bar Hama says that it is because of a concern with social intercourse; Rav Nahman says that it is because the beer is left uncovered, and we are concerned that it is left uncovered and may have become poisoned, as we learned on yesterday’s daf.
The Gemara relates that Rav rules that Armenian beer is permitted, although he would not allow his son, Hiyya, to drink it. The Gemara explains that Rav thought that it was forbidden because it was dangerous, but that the fermented hops counteracted any venom that might be in the beer, so that it would not be dangerous to a healthy person. Hiyya, who was, by his nature, physically weak, may have become injured by the beer, so his father did not allow him to drink it.
Hops, or humulus lupulus, which is used to this day as one of the ingredients in beer production, contains alkaloids and tannins which can play a role in breaking down snake venom that might be found in beer.
It should be noted that the Shulhan Arukh (Yoreh De’ah 114:1) accepts the tradition presented in the Gemara and forbids non-Jewish beer, but the Rema rules that beer made of grain or honey is permitted and he testifies that this was the common practice in his community.