Is Wine Tasting Nonsense?

wine tasting2Wine tasting has become one of the favorite playthings of the media with articles appearing periodically accusing wine tasters of being incompetent charlatans arrogantly foisting their fantasies on an unsuspecting public. But these articles seldom reflect critically on their conclusions or address the question of what genuine expertise in wine tasting looks like. In fact, articles in this genre routinely misinterpret the results of the studies they often quote.

The study that has received the most attention is from 2001. Frédéric Brochet at the University of Bordeaux, asked 54 wine experts to assess two glasses of wine, one red, the other white. But in fact the two wines were identical white wines, the “red” wine having been dyed with food coloring. All the experts used descriptors typical of red wines and failed to notice the wine was in fact white. But this study does not show that wine tasters are incompetent. The study relied only on smell, not taste which would more readily yield clues to the wine’s nature. More importantly, wine tasters are taught to use visual clues when trying to identify a wine using the deductive method. Given that the wine appeared red, trained wine tasters would have logically ruled out white descriptors. The study proves nothing about the expertise of wine tasters; only a lack of expertise in designing the study.

In a follow-up study, Brochet served wine experts two bottles, one with the label of a Grand Cru, the other labeled as an ordinary table wine. The wine in both bottles was identical and ordinary. The wine labeled as Grand Cru was highly praised; the one thought to be less expensive was roundly criticized. The conclusion this article attempts to draw is that all wine tastes the same and there is no distinction between cheap and expensive wine. But there is an alternative hypothesis that is much more plausible. We aren’t told who these experts were, but the results are not surprising. There is ample scientific evidence that judgments about wine, including those of experts, are influenced by reputation, price, and expectations. That is why wine tasters often taste blind so their judgments are not distorted by these factors. All this study shows is that our judgments are influenced by background beliefs—this is not news and the tendency of wine tasters to be influenced by price and reputation has been incorporated into wine tasting practice for decades. When objectivity matters, tasters are prevented from knowing price and reputation.

Other studies cast doubt on the rewards given to wines at festivals and county fairs where wine experts must assign numerical ratings to dozens of wines tasted blind in a single day. In one series of experiments, judges are, unbeknownst to them, given the same wine at different times throughout the day; the results show that the judges are wildly inconsistent in their evaluation. These wine competitions are problematic to begin with because palate fatigue sets in rather quickly. These competitions are opportunities for wineries to get publicity and marketing materials. Few wine experts take them seriously as attempts to objectively determine wine quality. But setting that worry aside, again the results are not surprising. Context is everything. What you taste will be influenced by the other wines being tasted at the same time. The assignment of numerical scores suggests a cardinal ranking but wine tasting in flights is inevitably comparative. The same wine will taste differently when tasted against different competitors. This is not because of a lack of expertise; it’s just a fact about how taste works. If you want objective results, then wine tasters must rest and recalibrate their palate to avoid results skewed by context. The most that can be drawn from these studies is that reasonably objective sensory evaluation requires carefully controlled conditions—philosopher David Hume discovered that in his 1757 essay On the Standard of Taste.

This article from the Guardian from several years ago entitled “Wine Tasting is Junk Science” gets the prize for most irrelevant headline. I don’t know anyone who thinks wine tasting is a science or that even expert wine tasters can achieve the level of accuracy required for scientific testing. Sharp disagreements among wine experts about the qualities and virtues of a particular wine are common. One critic thinks a wine is flabby and disjoint; the other thinks it is superb, and there is no way to settle the dispute. The fact that wine experts disagree in their evaluations is no surprise to anyone who pursues wine tasting seriously. Certainly, every expert I know admits the difficulties of wine tasting and readily grants that we often make mistakes. The comparison with science is a flopping red herring. The real question is whether the persistence of such disagreement among experts should undermine confidence in their expertise, which in any case would not be the expertise of a scientist.

One thing we know is that some of what we experience in a wine is a response to objective properties of the wine. We smell grassy or green pepper aromas in wine because of the presence of pyrazines; vanilla because of the presence of ethyl vanillate, etc. The perceived weight on the palate is a function of extract, residual sugar and/ or alcohol. When we taste we can succeed or fail to discern those objective properties because the signal they send is faint and easily masked. Novice wine tasters have trouble discerning flavor components in wine just as you might fail to taste the hint of rosemary in a sauce until someone points it out to you. But the relationship between perceived flavors and chemical compounds in the wine is well-established by science.

However, there is significant biological variation in human populations regarding the threshold for detecting compounds in wine. Some people will be more sensitive to certain compounds than others, and it is not yet clear to what degree these thresholds can be shaped by training. But variations exist in all our sensory mechanisms, color-blindness being the most obvious. There is no reason to think taste thresholds do not stabilize around a norm that allows most of our sensory judgments to be inter-subjectively valid despite variation on the margins. Thus, the existence of biological differences in taste mechanisms by themselves do not show that wine expertise is nonsense, anymore than the existence of colorblindness calls into question our ability to accurately refer to colors.

It is of course true that ordinary wine drinkers (as well as experts in some contexts) can be misled and seem to taste something that isn’t there. This is common when tasting in a group where comments by others may influence someone to misidentify the features of a wine. Furthermore, as noted, we can be influenced by price, reputation, expectations, personal relationships, and emotional commitments in ways that mislead us. But this is not evidence that wine tasting is nonsense—in fact quite the opposite. If there is such a thing as real expertise in identifying the properties of a wine, then it must be possible to get it wrong. If tastes, in general, were entirely subjective there would be no right answer to the question of whether, for instance, chocolate ice cream tastes of chocolate. No one really thinks that. The fact that expert wine tasters get it wrong so often is evidence that wine tasting is harder than identifying the presence of chocolate in ice cream—not that it is utterly capricious. So tastes are not so entirely subjective that our experiences of them have no relationship to an object.

But the question is whether experts are capable of limiting the influence of those factors that bias their judgments. And the answer is yes, at least up to a point. This is the purpose of blind tasting. Although blind tasting has many drawbacks, it does serve to insulate the taster from knowledge of the producer and price (single-blind tasting) and from the region and varietal (double-blind tasting). Furthermore, tasters can strive to eliminate environmental factors that have been shown to influence judgments about wine such as conversations, the style of music being played, and changes in the weather, etc. These are all factors that wine tasters can control by adjusting the environment in which they taste. Wine tasters, if they are to maintain credibility, must taste under the appropriate conditions. But that is no different from any other normative judgment we make. Our ability to make ethical judgments, for instance, is similarly influenced by environmental factors. We know (or should know) better than to make ethical judgments when we are excessively angry, fearful, under the influence of powerful desires, etc. Yet, it does not follow from the fact that ethical judgments can be influenced by irrelevant factors that all ethical judgments are subjective.

Nevertheless, each of us has a unique tasting history and a set of expectations based on that history from which there is no escape. This accounts, more than anything else, for disagreements among experts. We can’t step outside our past and taste something without that past influencing us. So the taste of wine (or anything else) is partly dependent on objective features of the world and partly dependent on how our view of those features has been shaped by past experience. The crucial question then is how much of a distorting lens is that past experience. Does it lead us to lose touch with the world or not? This is where systematic learning, the constant calibration of one’s taste to well-established standards, and a disciplined focus on getting things right comes into play. Experience sharpens our ability to perceive by improving our ability to isolate and identify those weak signals that less experienced tasters miss. Furthermore, prejudices can be overcome and influences can be prevented from distorting our perceptions if we become aware of them and have the will to limit their influence. The more knowledge you have about wine regions, vinification processes, etc. the more you can use that knowledge to shape your tasting experience to conform to objective properties of the wine. The fact that some people after years of study are able to pass the very rigorous “Masters of Wine” program (there are currently only 312 worldwide) is evidence that tasting expertise is real—they are not consulting oracles or hallucinating their answers.

So wine tasting expertise is neither arbitrary nor useless. It is a matter of having the experience and reflective awareness to reduce the role of factors that might distort our impression of a wine. Expertise can’t eliminate all subjectivity but it can reduce some personal biases such that with extensive background knowledge they give the taster a clearer impression of the wine than they would have without the expertise.

3 comments

  1. You do Professor Brochet a disservice by stating that : “The study proves nothing about the expertise of wine tasters; only a lack of expertise in designing the study.”

    Nonsense. The study shows, as you note later on in your article, that wine tasting can be imprecise, and that even experts can be misled by external factors (such as assuming the wine had not been doctored with coloring.) and their conclusions, as such, are suspect. In his subsequent experiment, the expert wine tasters were again misled by external communication (the labels) and allowed that information to influence their analysis of the wines.

    Brochet’s point in all of this is to demonstrate the importance of eliminating these external factors to give experts the opportunity to truly taste the wine–not the label or other extraneous influence. You suggest the same in your discussion–but then claim that true experts can achieve success even while being influenced by these factors. Brochet has evidence you are mistaken. Until you provide scientific results that disprove his, you are on weak ground here.

    1. Hi Paul,
      My comment about a poorly designed study is referring to the first study by Brochet. I don’t think that study shows us much because it ignores the decision tree used by blind tasters. The color of the wine is not an external factor but part of the evidence base for determining wine properties.

      I agree with you about the second study. It shows the importance of double blind tasting when objectivity matters.

      And neither study addresses the question of whether experts can overcome biases via meta-cognition.

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