Size does matter says Cambridge study

Serving wine in larger glasses may trick the brain into thinking it is drinking less and encourage people to order more, according to a study by Cambridge University.

Sales were monitored over a 16-week period to examine whether the size of glass affects alcohol consumption.

The study found that serving wine in a larger wine glass led to a 10% increase in wine sales, even when the amount of wine served in each size glass was the same.

A team from the Behaviour and Health Research Unit (BHRU) at the University of Cambridge, together with Professor Marcus Munafo from the University of Bristol, carried out a study in The Pint Shop in Cambridge from mid-March to early July 2015 to examine whether the size of glass in which alcohol is served affects consumption.

At its restaurant and separate bar area, wine could be ordered in 125ml or 175ml servings by the glass, which was usually a standard 300ml size. Over the course of a 16-week period, the size of the wine glasses were changed at fortnightly intervals, alternating between the standard (300ml) size, larger (370ml) and smaller (250 ml) glasses.

Researchers found that the volume of wine purchased daily was 9.4% higher when sold in larger glasses compared to standard-sized glasses. This effect was mainly driven by sales in the bar area, which saw an increase in sales of 14.4%, compared to an 8.2% increase in sales in the restaurant.

“It’s not obvious why this should be the case, but one reason may be that larger glasses change our perceptions of the amount of wine, leading us to drink faster and order more,” said Dr Rachel Pechey from the BHRU at Cambridge. “But it’s interesting that we didn’t see the opposite effect when we switched to smaller wine glasses.”

There was no conclusive evidence to show that sales were different with smaller compared to standard-sized glasses. The study suggested that serving wine in smaller glasses, and avoiding larger glasses, could therefore help reduce the amount that people drink, but that using larger glasses could help increase sales within the on-trade.

“We need more research to confirm this effect, but if it is the case, then we will need to think how this might be implemented,” said Professor Theresa Marteau, director of the unit. “For example, could it be an alcohol licensing requirements that all wine glasses have to be below a certain size?”

The research was funded by the Department of Health and was In a study published today in the journal BMC Public Health.