Beer is certainly wrong. Hops and heresy, turkeys and beer, came into England all in one year. The turkey dates that to the early 16th century or after. I'm not sure which heresy, Luther sounds a bit late (about 1518-1520), and some authorities say hops arrived late 15th century, but it's all a long time after Robin Hood, early 13th century for King John and Richard the Lionheart.

Prioresses would be far more likely to drink wine anyway. I've never seen a nun with a beer gut.