Effect of glass markings on drinking rate in social alcohol drinkers

Background The main aim of these studies was to explore the influence of volume information on glassware on the time taken to consume an alcoholic beverage. Methods In Study 1, male and female social alcohol consumers ( n = 159) were randomised to drink 12 fl oz of either low or standard strength lager, from either a curved glass marked with yellow tape at the midpoint or an unmarked curved glass, in a between-subjects design. In Study 2, male and female social alcohol consumers ( n = 160) were randomised to drink 12 fl oz of standard strength lager from either a curved glass marked with ¼, ½ and ¾ volume points or an unmarked curved glass, in a between-subjects design. The primary outcome measure for both studies was total drinking time of an alcoholic beverage. Results In Study 1, after removing outliers, total drinking time was slower from the glass with midpoint volume marking [mean drinking times (min): 9.98 (marked) vs. 9.55 (unmarked), mean difference = 0.42, 95% CI: -0.90, 1.44]. In Study 2, after removing outliers, total drinking time was slower from the glass with multiple volume marks [mean drinking times: 10.34 (marked) vs. 9.11 (unmarked), mean difference = 1.24, 95% CI: -0.11, 2.59]. However, in both studies confidence intervals were wide and also consistent with faster consumption from marked glasses. Conclusion Consumption of an alcoholic beverage may be slower when served in glasses with volume information. Replication in larger studies is warranted.