Determination of Alcohol in Low Alcohol and Non Alcohol Beers by Gas Chromatography-FID, Near Infra Red Spectroscopy and Catalytic Combustion Methods

Abstract

Submitted by A. Toivola, P. Varjú and J. Torrent on behalf of the Analysis Committee of the European Brewery ConventionMethods for the determination of alcohol in low and non alcohol beers by gas chromatography with flame ionisation detection (GC-FID), near infra red spectroscopy (NIR) and catalytic combustion (CC) were collaboratively tested by the Analysis Committee of the European Brewery Convention according to ISO Standard 5725 in order to determine their suitability for publication in Analytica-EBC. Accuracy, repeatability (r 95 ) and reproducibility (R 95 ) values are presented.The GC-FID method was found to have better within and between laboratory precision than the other two methods for the determination of alcohol in the non alcohol (0.007-0.08% V/V) beers and comparable precision for the low alcohol (0.37-0.81% V/V) beers. Over the whole range 0.007 to 0.81% V/V of alcohol, repeatability (r 95 ) was found to be dependent on the mean value and was 0.096 m % V /V whereas reproducibility (R 95 ) was found to be independent of the mean value and was 0.090% V/V. The gas chromatographic method is recommended for inclusion in Analytica-EBC as the reference method for the determination of alcohol in non and low alcohol (<1.0% V/V) beer samples.The NIR and CC methods have acceptable within and between laboratory precision figures for the determination of alcohol in the low alcohol beers.For the NIR method, repeatability (r 95 ) and reproducibility (R 95 ) were found to be independent of the mean value and were 0.022% V/V and 0.103% V/V respectively over the range of alcohol tested (0.007-0.81% V/V). The method is recommended for inclusion in Analytica-EBC for the determination of alcohol in low alcohol beer samples (>0.37% V/V).For the CC method, both repeatability (r 95 ) and the reproducibility (R 95 ) were found to be independent of the mean and were 0.016% V/V and 0.087% V/V respectively over the range of alcohol tested (0.007-0.81% V/V). The method is recommended for inclusion in Analytica-EBC for the determination of alcohol in low alcohol (>0.37% V/V) beer samples.