Hops have long been evaluated through aroma and bitterness. That framework no longer reflects how hops behave in modern brewing. As dry hopping has become central to many beer styles, brewers are increasingly exposed to unintended re-fermentation, variability in final gravity, and instability in package. These effects are not random. They are driven, in part, by enzymatic activity present in hops. This article by Francesco Lo Bue and Philip Wietstock, Professor