The Colorimetric Determination of Isobutyl and Isoamyl Alcohol in Fusel Oil Separately

Abstract

The amounts of isobutyl and isoamyl alcohol which are the main constituents of fusel oil are determined fractionally. Isobutyl and isoamyl alcohol give different colors by treatment with p-dimethylaminobenzaldehyde in sulfuric acid. Using this color difference the amount of each of these alcohols in fusel oil is determined colorimetrically. These alcohols arise during alcoholic fermentation and are concentrated in the distillate by distillation, and affect the flavor of distilled spirits, such as brandy and whisky, i.e., butyl alcohol is buttery and amyl alcohol is aromatic. So determination of the amounts of these alcohols fractionally in these spirits furnishes a useful criterion for evaluating the character of these spirits.