The Bureau of Alcohol, Tobacco and Firearms now distinguishes between vodka and "flavored vodka" that contains added citric acid, and has developed a method for telling the difference. "During the comment period, ATF secured an outside testing firm, Odor Science and Engineering (OS&E), to conduct independent testing on sensory threshold levels for citric acid addition to vodka." The taste panel was made up of "ten experienced sensory panelists," under a methodology known as "Standard Practice for Determination of Odor and Taste Thresholds By a Forced-Choice Ascending Concentration Series Method of Limits" (ASTM Procedure E-679).

†