Fifteen expart sake tasters judged sensory properties of 5 fatty acids. Firstly, by adding each fatty acid to 15% ethanol solution, threshold concentrations were measured and determined: 39.3 ppm for acetic acid, 2.7 ppm for n-butyric acid, 2.3 ppm for n-caproic acid, 2.4 ppm for n -caprylic acid and 3.1 ppm for n-capric acid, respectively. Thepanelists described acidic smell for acetic acid and n-butyric acid and oily one for the others. Secondly, sensory properties of the fatty acids were examined. Four types of sake added with 30 or 60 ppm acetic acid gave similar sensory quality as those without added acetic acid. Whereas, sake added with n-capric acid, n-caprylic acid, n-caproic acid or n-butyric acid at 4 or 8 ppm gave poor than that without added fatty acid. Many panelists perceived oily, dusty, filtration and hukuroka smells for those fatty acids.