פירוש על עבודה זרה 66:4

According to Rava, the beer put in these wine jugs will nullify the taste of the wine and therefore it is permitted. According to R. Nahman and R. Judah it does not. As someone who knows quite a bit about beer, I must say that R. Nahman and R. Judah are usually correct. This is why some beer is allowed to age in wine barrels. It enriches the taste.

Ravina follows Rava and therefore he ruled that R. Hiyya could actually put beer into these vessels. R. Hiyya got confused and put wine in there. Rava was not concerned that by allowing people to use these vessels for beer, they would come to use them for wine. This case was just an accident.