Abstract: In order to control the content of dimethyl sulfide (DMS), a substantial contributor to the aroma and flavor of many commercial beers, 15 beer samples marketed in China were analyzed by gas chromatography with hydrogen flame ionization detection. Variations in the contents of DMS, S-methylmethionine (SMM), and dimethyl sulfoxide (DMSO) were traced during beer fermentation. The results showed that the content of DMS in 47% of the beers exceeded 60 μg/kg. Notably, 71% of the Ale-branded beer samples were found to contain DMS contents higher than 60 μg/kg (with the highest value of 105 μg/kg). Significant variation (up to 160%) was found among 10 commercial malts in the country in the contents of DMS and dimethyl sulfide precursor (DMSP). The contents of DMS and DMSP in most wheat malts were lower than those in Australian malts. After being boiled for 40 min at pH 5.6, the content of DMS in worts decreased by 92%, and the half-life of SMM was 31 min. Additionally, the content of DMS significantly decreased by up to 41% during the vigorous fermentation stage.

Key words: beer, fermentation, dimethyl sulfide, S-methylmethionine, dimethyl sulfoxide, dimethyl sulfide precursor