According to the chemistry of sour taste proposed in this study, the following strategy to reduce the sensory can be provided "not only reduce free hydrogen ions, (namely elevate pH value), but also reduce the undissociated hydrogen ions contained in the protonated acid species." In these acids, where the pKa isless than 2.0, it is no use reducing its content, as the acid species is almost all anion which does not bind hydrogen ions at a pH of about 4.0. For acids in which pKa is over 2.0, it is necessary to reduce their content in beer for the purpose of lowering the sour taste. The common organic acids in beer, such as acetic acid, lactic acid, citric acid, succinic acid, pyruvic acid and fumaric acid, usually have pKa values of more than 2.0. Therefore it will be necessary to reduce these organic acid concentrations if the sensory sourness of a beer is to be alleviated.