A radio-dilution technique has been developed for estimating levels of dimeric polyphenols in barley, malt, wort, and beer. Levels present in a number of different cultivars of barley vary from 130 to 350 mg/kg. When barley is malted, the loss of dimeric polyphenols is normally less than 15%. However, large losses of dimers occur during mashing and wort boiling, and smaller losses usually take place during fermentation and conditioning. The higher the level of dimeric polyphenols in the malt, the higher the level in the derived beer.