The present study examined a winemaking method for producing a wine containing higher yaminobutyric acid (GABA) levels. Exposure of the Muscat Bailey A grape to carbon dioxide gas resulted in increased GABA content and decreased glutamic acid content in the juice. The mutant MA 3719 carrying gap 1 put 4 uga 4 triple mutations isolated from wine yeast Saccharomyces cerevisiae was unable to be grown on a minimal plate supplemented with GABA as the sole nitrogen source. Laboratory scale winemaking using the Muscat Bailey A grape exposed to carbon dioxide gas for 48hours and the mutant MA 3719 was carried out. No assimilation of GABA was observed during fermentation, and the resulting wine contained higher levels of GABA.