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For the purpose of studying the possibility to use the barley as a raw material in vinegar manufacturing process, several factors related to the fermentation of acetic acid were investigated. The optimum quantity of sweet liquor prepared by koji method in medium was 30-40%. When koji of A. oryzae, commercial enzyme products and malt were used for the saccharification of the barley, the production rates of acetic acid during log period were 0.056%/hr, 0.025%/hr, 0.03896/hr and lag period were 22 hours, 48.5 hours and 25 hours, respectively. These results indicate that the saccharifying method using koji of A. oryzae is superior to that by the commercial enzyme products or malt for the acetic acid fementation. The optimum initial acidity was 2% and the proper initial ethanol degree were 4-6% in metium. In a submerged culture process using a jar fermentor, lag period was 15 hours, and acetic acid fermetation period was about 45 hours. In the sensory test of barley vinegar and commercial vinegar of the market, barley vinegar was superior to the vinegar in market with respect to tastes.
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