Any serious wine drinker will tell you she can distinguish between inexpensive, low-quality wine and the fancy premium-priced stuff. She may also claim the ability to discern the difference between wine made from different grapes, or produced in different regions of the world. Yet some studies have found that even so-called experts are unable to figure that “red wine” was actually a white wine dyed red, and nearly everyone seems to be swayed by the label on a wine bottle. Wouldn’t we all just be better off if we simply kept an old empty bottle of fine vintage wine and refilled it as necessary with the cheapest boxed wine we could find?
Not necessarily. Ordinary individuals can be trained to tell the difference between wines along a number of different dimensions. One key aspect of the flavor of a wine is “mouth feel,” which, as you might guess, describes the feeling of a wine inside of the mouth, before it is swallowed, and independent of smell. Can ordinary individuals be trained to discern wines solely based on mouth feel? Does everyone “feel” wine the same way?
Researchers have known for some time that not everyone has the same ability to detect tastes. Some people — “super-tasters” — are especially sensitive to a wide range of tastes. As it turns out, whether or not you’re a super-taster may come down to your ability to detect a single molecule: 6-n-propylthiouracil, or PROP for short. Those who can taste PROP find it incredibly bitter, but super-tasters are also extra sensitive to saltiness, sweetness, and even tactile sensations in the mouth.
Gary Pickering and Gordon Robert recruited 17 volunteers to sample a set of wines twice a week for 7 weeks (before you rush to sign up for their next study, be advised that all tasters had to spit out their drinks after sampling!). All the tasters were tested for PROP sensitivity, and 8 of them were found to be super-tasters. The study was conducted with nose plugs so that solely mouth-feel was rated.
Four different red wines were rated for mouth feel along dimensions generated by the tasters themselves. While they could use formal wine-tasting terminology, they were allowed to use any terms they wished to describe the mouth feel of the wines. Within a few weeks the tasters settled on 13 different sensations to describe the wines: Acidity, bitterness, saltiness, viscosity, heat/irritation, tingle, particulate (both in mouth and after spitting), smoothness (in mouth and after spitting), grippy/adhesive, mouth coat, and overall astringency. Reference scales from 0 to 150 were created for each sensation – for example, “particulate” could range from 0 (Johnson’s baby powder) to 150 (coarse sand). Most of the actual ratings chosen by tasters were between 0 and 10.
So after all this training, could tasters distinguish between the wines in a blind taste test? For the final tasting, they sampled the wines in a room lit with red light, so they weren’t even able to visually distinguish between the samples. Here’s the result for just one dimension of taste, smoothness after spitting:
Not only were most ratings for each wine significantly different from each other, but the super-tasters’ ratings were significantly different from the non-tasters for nearly every variety of wine. This difference between super-tasters’ and non-tasters ratings held for every dimension of mouth feel except for bitterness and viscosity.
Whether an individual is a PROP super-taster is determined by genetics, and clearly super-taster status has an important impact on taste for wine. But whether or not an individual is a super-taster, it’s clear that with some training, many individuals can readily discern many differences between varieties of wine. It would be interesting to see how the results of a study like this might change if the wines were labeled (and perhaps sometimes mislabeled) during testing.
Pickering, G.J., Robert, G. (2006). Perception of mouthfeel sensations elicited by red wine are associated with sensitivity to 6-n-propylthiouracil. Journal of Sensory Studies, 21(3), 249-265. DOI: 10.1111/j.1745-459X.2006.00065.x