The Australian Wine Research Institute’s Analytical Service - Analyses

Ethyl carbamate

Ethyl carbamate (or urethane) is formed during the production of wine resulting from the reaction between urea or other related precursors and ethyl alcohol. Urea is derived largely from the yeast metabolism of arginine, which is an abundant amino acid in grape juice. The rate of production of ethyl carbamate is influenced by the concentration of urea or other precursors and temperature. Wines made from grape varieties which contain high levels of arginine can have relatively higher levels of ethyl carbamate. In the production of fortified wines, partially fermented must is fortified at a time when the concentration of urea is high. This can lead to higher levels of ethyl carbamate in fortified wines relative to table wines. Ethyl carbamate is a suspected mild carcinogen, the maximum level is, therefore, limited by regulation in many countries.

An analytical method employing extraction, cleanup and gas chromatography/mass spectrometry (GC-MS) operating in selected ion monitoring mode has been developed for the determination of ethyl carbamate in wine.