A drink is a drink? Variation in the amount of alcohol contained in beer, wine and spirits drinks in a US methodological sample

Background: Empirically based estimates of the mean alcohol content of beer, wine and spirits drinks from a national sample of US drinkers are not currently available. Methods: A sample of 310 drinkers from the 2000 National Alcohol Survey were re-contacted to participate in a telephone survey with specific questions about the drinks they consume. Subjects were instructed to prepare their usual drink of each beverage at home and to measure each alcoholic beverage and other ingredients with a provided beaker. Information on the brand or type of each beverage was used to specify the percentage of alcohol. Results: The weighted mean alcohol content of respondents' drinks was 0.67 ounces overall, 0.56 ounces for beer, 0.66 ounces for wine and 0.89 ounces for spirits. Spirits and wine drink contents were particularly variable with many high-alcohol drinks observed. Conclusions: While the 0.6-ounce of alcohol drink standard appears to be a reasonable single standard, it cannot capture the substantial variation evident in this sample and it underestimates average wine and spirits ethanol content. Direct measurement or beverage-specific mean ethanol content estimates would improve the precision of survey alcohol assessment.