The hypothesis that other intermediate compounds (e.g. hydroxyl radicals: OHradical dot, 1-hydroxyethyl radical, sulphur and alkoxyl radicals) play a main role in the oxidative reactions of alcoholic beverages is consistent with findings on aerobic oxidation during early stages of beer brewing in which a high catalase dosage caused only a 20% reduction of the initial rate of radical formation (i.e. due to H2O2), whereas superoxide dismutase had no effect on the oxidation rates as determined by electron spin resonance (ESR)-based method with the spin trap alpha-4-pyridyl(1-oxide)-N-tert-butylnitrone (POBN)