Iowa State University researchers have found most people tend to over-pour when it comes to getting just one serving of wine in a glass.
“The basic idea is that people are very influence-able in their consumption,” says Laura Smarandescu, an ISU marketing professor, “so even though we think we are in total control of our reactions and decisions, a lot of times environmental cue influence our behavior.”
The study asked participants to pour one serving of wine into glasses of various sizes, plus some glasses were clear while others had a color. The results? Participants poured about 12 percent more wine into a wide glass. In addition, holding the glass while pouring led people to surpass a single serving by about 12 percent.
“Basically, people are very bad at estimating volumes,” Smaranescu says. “In general, we focus on the vertical dimension more than the horizontal. and so we actually end up pouring less in narrow glasses than we pour in wide glasses, so that’s what we found.”
A previous study tested bartenders and found even the professionals over-pour. ”Although they are of less magnitude than the general population,” Smarandescu says.
The non-bartender participants in this latest study poured about nine percent more red wine into a clear glass then into a glass that had some sort of color tint. According to the National Institute on Alcohol Abuse and Alcoholism, five ounces is the standard serving size for wine. The ISU research team collaborated with professors at Cornell University on this study, which was published in the “Substance Use and Misuse” journal.