The importance of polyphenols in beer Polyphenols in beer mainly come from barley and hops. About 80% of them come from barley and 20% from hops. The phenols in barley are about 0.1% ~ 0.3% of its dry weight, mainly distributed in wheat husk, aleurone layer and endosperm. With the dissolution of malt in the process of malting, it is free and brought into wort and beer through the saccharification process. Phenolic substances in hops account for 4%~10% of the dry matter, mainly distributed in the bracts and rachis of hops.