Does glass shape influence the speed at which you consume beer? Are curved pot or schooner glasses more common in pubs because they seem to empty quicker and then entice you to buy more? Can you judge the half-way point of a fluted beer glass?

These questions may rarely be considered while a drinker enjoys their favourite brews. However, the optical illusion of a drinking vessel’s fullness may be more influential on your time at the pub than you ever thought.

A new peer reviewed study, published in the PLOS ONE science journal, has tested the influence of glass shape on the consumption rate of beverages. It is a first in academic studies to examine whether glass shape directly influences drinking behavior.

Researchers from the School of Experimental Psychology at the University of Bristol conducted a comparison of straight and curved glassware on the speed at which social drinkers from Bristol in the UK down a beer verses a soft drink.

Lead by experimental psychologist Dr Angela Attwood and funded by a grant from Alcohol Research UK, the research gathered 160 people, with an 50/50 male/female split, for an afternoon beverage and a reward of 10 pounds.

The straight and curved glasses used in Dr Attwood’s study.

The participants were divided into eight groups and then provided with one of eight combinations from a selection of two different glasses (a straight-sided glass or curved flute glass) and two different beverages (a lager from the Saint-Omer brewery in France or a soft drink). This provided each group with either a full (374 ml) or half-full (177 ml) beer or soft drink in a curved or straight glass.

To assess drinking times, the groups were filmed as they drank whilst watching a nature documentary deemed emotionally neutral, which provided participants with something to do other than just rapidly drink. The experiment also used filler tasks as a diversion tactic to disguise the aim of the study, preventing participants from augmenting their approach to drinking from different types of glasses.

On a separate occasion, the participants each completed computerised tests that asked them to visually judge the perceived midpoint of various levels of fluid in photographs of different shaped glasses.

Total Drinking Time for full volume by Drink and Glass type.

From the drinking tests, the researchers found that the beer was consistently consumed faster by the group drinking a full glass out of curved flute glasses. This group finished their beer in under 8 minutes on average, whilst the groups drinking full levels of beer from straight-sided glasses nursed their beers for an extra 5 minutes.

In contrast, the two groups that started with half-full glasses showed no significant difference in the time taken to drink from either curved or straight glasses.

The published paper concludes: “Participants were 60% slower to consume an alcoholic beverage from a straight glass compared to a curved glass. This effect was only observed for a full glass and not a half-full glass, and was not observed for a non-alcoholic beverage. Participants also misjudged the half-way point of a curved glass to a greater degree than that of a straight glass, and there was a trend towards a positive association between the degree of error and total drinking time.”

The mechanisms underlying this effect are not still understood. Dr Attwood’s hypothesis is that people drinking soft-drink don’t pay any attention to their consumption rate because there is no impact from alcohol, so drinking pace is irrelevant to them. A beer drinker will be more considered of the time taken to half empty their glass because of the alcohol’s influence.

“People often talk of ‘pacing themselves’ when drinking alcohol as a means of controlling levels of drunkenness, and I think the important point to take from our research is that the ability to pace effectively may be compromised when drinking from certain types of glasses,” noted Dr Attwood.

The research team hopes their findings will lead to new methods that will help curb binging on beer. Whilst governments and health authorities consider measures such more legislation, tighter licensing controls on licensed venues and increased taxes on alcohol, Dr Attwood believes that her research shows a more rational approach to slowing the drinking sessions of people in pubs.

Dr Attwood suggests that the reason for the increased drinking speed is that the halfway point in a curved glass is ambiguous. Hence, a simple solution would be to mark beer glasses with the accurate halfway point.

“We can’t tell people not to drink, but we can give them a little more control.”

Some academics have reacted to the study, suggesting that the allowances for classifying the participants as “social drinkers” were too loose, allowing in drinkers who will naturally drink quickly just to get drunk. Also, the pool only included staff and students from the University of Bristol or residents from the immediate area, which may have limited the cross-section of population diversity.

The study does present a solid foundation for further research that could really tackle any questions and concerns on whether drinking pace is perceptual and can influence binge drinking. A more comprehensive study would need to investigate the effects of drinking out of a can, bottle, and multiple shaped beer glasses such as, tulips, dimpled steins, hexagonal tumblers, Belgian chalices and snifters.

At Australian Brews News we are strong advocates for the enjoyment of beer through responsible drinking, as well as for both drinking beer from a glass, to experience the full aroma and flavour characteristics of a brew, and for the selection of appropriate glassware to enhance its drinking performance depending on the beer’s style.

If Dr Attwood’s finding are further validated, breweries and beer educators may find that their current leanings for the best shaped glasses for various beers actually differ from that the preference of health campaigners and regulators.

Thankfully, one solution to that problem is easy – just drink slowly to best enjoy your beer. If you’re drinking too fast, maybe you should check yourself on why…or maybe it’s just not good beer.

Reference: Attwood AS, Scott-Samuel NE, Stothart G, Munafò MR (2012) Glass Shape Influences Consumption Rate for Alcoholic Beverages. PLoS ONE 7(8): e43007.