Another Attack on Wine Expertise

The recent article by Hayes and Pickering in the American Journal of Enology and Viticulture (behind a paywall) has gotten a lot of attention from the popular press, most of it undeserved.

The research by Hayes and Pickering purports to show that professional wine tasters have a greater ability to detect bitter flavors than non-experts. As reported by Penn State’s press release on the research:

Hayes said that the participants sampled an odorless chemical — propylthiouracil — that is used to measure a person’s reaction to bitter tastes. People with acute tasting ability will find the chemical — also referred to as PROP, or prope — extremely bitter, while people with normal tasting abilities say it has a slightly bitter taste, or is tasteless.

However, from this interesting bit of research, the authors draw a sweeping, entirely unsupported conclusion:

Hayes, who worked with Gary Pickering, professor of biological sciences and psychology/wine science, Brock University, Ontario, Canada, said that the acute taste of wine experts may mean that expert recommendations in wine magazines and journals may be too subtle for average wine drinkers to sense.

And the press has published an eyeball-snatching flurry of articles and blog posts telling consumers that they have no reason to listen to wine experts since the ordinary person cannot detect the flavors discerned by wine experts.

“Wine experts are more likely to have a very exquisite, acute sense of taste that the rest of us can’t sense,” said Hayes, one of the authors of the report, in a telephone interview. “Some of that is biology.”

The problem is that the research doesn’t warrant the conclusions the researchers draw from it.

First of all, there are hundreds of compounds in wine that account for its flavor and texture. A greater sensitivity to bitterness doesn’t entail a greater sensitivity to these other compounds.

Secondly, Propylthiouracil is the substance typically used to identify “supertasters” whose sensitivity to bitterness is explained by the larger number and greater concentration of papillae that make up their taste buds. But supertasters are also primarily women, and will tend to also dislike broccoli, bitter greens, chocolate, coffee, soy, sugar, and fat. Moreover supertasters tend to drink less alcohol than non-supertasters since they dislike its bitter flavor. I doubt that wine professionals tend to dislike alcohol! Or these other substances either. And they are not disproportionately women. At the very least, researchers should try to cross-reference these other characteristics before drawing sweeping conclusions.

In addition, Hayes is suggesting that the higher sensitivity to bitterness is explained by a genetic predisposition. But the tendency to identify and dislike bitterness among wine professionals may be a learned response. Bitterness in wine is an indicator of all sorts of quality-reducing characteristics of the wine-making process including, excess alcohol, excess tannin, poorly integrated oak,  and under-ripe grapes, which can make bitterness more apparent. It is likely that wine professionals have trained themselves to detect bitterness and to judge it unpleasant, even when presented with a single, bitter-tasting substance, as it typically indicates poorly made wine. But if it is a learned response, then consumers have more reason to listen to wine critics since their expertise can help consumers better evaluate the wine they purchase.

I have not read the original article that contains the research but, as far as I can tell from the reports, the research makes no attempt to distinguish biological influence from learned response. There is ample scientific evidence that taste is cognitively penetrable. That is to say, what we think about the wine will influence what we taste. Unless one knows what to look for and learns to discriminate between very subtle flavor components, many of the qualities of wine will be undetectable to the ordinary consumer—and their enjoyment will be less than what it could be with more knowledge.

It is no doubt true that our ability to taste is influenced by biology and that people differ with regard to their biological characteristics. It hardly follows from this fact that learning plays no role in determining taste. As with most of our characteristics, taste is a complex interaction between biology and environmental influence, i.e. learning. Yet, Hayes seems to deny that interaction when he concludes consumers should not listen to experts.

Scientists are good at science. They tend to be less competent when it comes to making normative judgments about the implications of their research, and often positively ham-handed in disseminating the meaning of their research to the public.

And publicity-seeking claims just get in the way. Had Hayes promoted his findings that wine professionals differ from non-professionals in their judgments about bitterness, only wine professionals would have paid attention. Adding the nonsense about what consumers should do got lots of eyeballs but it wasn’t science.

It just contributes to the strain of “anti-expertise” currently coursing through American society.

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