Alcohol content of beer and malt beverages: Forensic considerations

Beer consumption is commonly an issue in a medico-legal setting, requiring estimates either of a likely blood alcohol concentration (BAC) for a given pattern of consumption or vice versa. Four hundred and four beers and malt beverages available for sale in the State of Washington were tested by gas chromatography for their alcohol content. Considerable variability in the a lcoholic strength was found, even within the same class. Overall the range of concentrations was 2.92%v/v to 15.66%v/v. The mean alcohol concentration for ales was 5.51%v/v (SD 1.23%v/v), and for lagers, 5.32% (SD 1.43%v/v). Some specialty brews had characteristically higher or lower mean concentrat ions; ice beers 6.07%v/v, malt liquor 7.23%v/v, light beer 4.13%v/v, season al ales 6.30%v/v. Six brands of lager and four light beers account for the majority of all beer sales in the United States, and the mean alcohol conce ntration for these products was measured as 4.73%v/v and 4.10%v/v respectiv ely. Few of the beers (17%) were labeled with respect to alcohol content, a nd in some cases, there was a significant disparity between the concentrati on listed on the label, and the measured alcohol concentration. Toxicologis ts need to exercise caution when performing Widmark type calculations, usin g all available information to select the most appropriate estimate for alc oholic strength of a beer or malt beverage.