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.