Hop chemistry and wort boiling

Abstract

Hops and hop-derived products are used primarily to impart bitter flavor to beer. Bitterness in the form of iso-±-acids is the primary flavor impact of hops though under some processing conditions hop aroma character can survive into beer. Iso-±-acids also support foam formation and, in some beers, have anti-microbial activity. The bright yellow, glistening lupulin glands of the hop cone, located at the base of the bracteoles, contain all of the material of interest to brewers. These materials comprise two components called the total resin and the essential oil.