Wine glass size and wine sales: A replication study in two bars05 Dec 2017
Objective. Wine glass size may influence perceived volume and subsequently purchasing and consumption. Using a larger glass to serve the same portions of wine was found to increase wine sales by 9.4% (95% CI: 1.9, 17.5) in a recent study conducted in one bar. The current study aimed to replicate this previous work in two other bars using a wider range of glass sizes. To match the previous study, a repeated multiple treatment reversal design, during which wine was served in glasses of the same design but different sizes, was used. The study was conducted in two bars in Cambridge, England, using glass sizes of 300ml, 370ml, 510ml (Bar 1) and 300ml and 510ml (Bar 2). Customers purchased their choice of a 750ml bottle, or standard UK measures of 125ml, 175ml or 250ml of wine, each of which was served with the same glass. Results. Bar 1: Daily wine volume purchased was 10.5% (95% CI: 1.0, 20.9) higher when sold in 510ml compared to 370ml glasses; but sales were not significantly higher with 370ml vs. 300ml glasses (6.5%, 95% CI: -5.2, 19.6). Bar 2: findings were inconclusive as to whether daily wine purchased differed when using 510ml vs. 300ml glasses (-1.1%, 95% CI: -12.6, 11.9). These results provide a partial replication of previous work showing that introducing larger glasses (without manipulating portion size) increases purchasing. Understanding the mechanisms by which wine glass size influences consumption may elucidate when the effect can be expected and when not.