Evaluation of an Enzymatic Method for Estimating Ethanol in Wines Using an "Enzyme Kit"

Abstract

A commercially available enzyme reagent "kit" for determining ethanol in body fluids was modified for assaying wine ethanol levels. The procedure involves direct analysis of a diluted wine sample, using the reaction catalyzed by alcohol dehydrogenase where reduced nicotinamide adenine dinucleotide (NADH) is detected photometrically as a measure of ethanol in a sample. The procedure showed good recovery of ethanol from freeze-dried, dealcoholized samples, which were reconstituted with known amounts of ethanol. The standard deviation for assays on these reconstituted samples was 0.12-0.16%. A limited comparison of the enzymatic assay with methods involving analysis of a distillate with dichromate oxidation and hydrometers showed agreement between the procedures. The enzyme assay was not precise enough for very accurate work, but it does offer speed as well as little sample or reagent preparation for estimating wine ethanol levels.