Modification of the levels of polyphenols in wort and beer by addition of hexamethylenetetramine or sulfite during mashing

The effects of addition of hexamethylenetetramine (HMT) or sulfite during m ashing on the polyphenol content and oxidative stability of wort and beer h ave been evaluated in a series of laboratory mashings and pilot brews. HMT reduced the concentration of catechin, prodelphinidin B-3, and procyanidin B-3 in wort and beer, whereas the concentration of ferulic acid. was unaffe cted. Sulfite had only a minor effect on the concentration of phenolics in wort and beer. Addition of HMT or sulfite, during mashing increased the oxi dative stability of the beer slightly as judged by the tendency of formatio n of radicals (ESR spin trapping technique), although sensory analysis gave identical flavor acceptance scores to beers produced from untreated and HM T-treated wort and lower scores to beer from sulfite-treated wort. No diffe rence in the oxidative stability of the differently treated sweet worts cou ld be detected as judged by the rate of formation of radicals. HMT addition during mashing has thus been demonstrated to be a valuable experimental to ol to control the level of polyphenols in wort and for producing brews with various levels of polyphenols from a single malt.