COMMENTARY

Wine on the Brain

Authors examine tasting through brain searchery

By Neal D. Hulkower

What comes to mind when one engages with a glass of wine?  And how does technology-assisted “brain searchery” help us find the answers and make us more attentive wine tasters?

These sensory and non-sensory contributions to our wine enjoyment are explored from two different perspectives in “Neuroenology: How the Brain Creates the Taste of Wine” (Columbia University Press, 2017) by Yale neuroscience professor Gordon M. Shepherd and “I Taste Red: The Science of Tasting Wine” (University of California Press, 2016) by British wine writer, wine judge and plant biologist Dr. Jamie Goode — the latter was announced as the Domaine Faiveley Wine Book of the Year at the 2017 Louis Roederer International Wine Writers’ Awards.  

Shepherd and Goode take readers through the basics of how our senses work with each other; all five come into play when we interact with wine.  The eyes drink first, taking in the color and setting expectations. With the first sniff of the glass, orthonasal olfaction (what we smell when breathing in) triggers receptors in the nose. With the first sip, the wine blends with saliva activating retronasal olfaction (mouth smell), which creates flavor from smell molecules traveling through the nasal passages as one imbibes. Different areas of the mouth contain sensors reacting touch, pressure, temperature and pain, creating the mouthfeel of the wine. Taste bud receptors react to various chemical molecules called tastants, that are contained in the wine-saliva mix and transmit signals to the brain. The sounds made by the wine as it moves around the mouth and is swallowed contribute to the experience.  In the brain’s orbitofrontal cortex, crossmodal processing combines smell and taste along with the other senses to create flavor.  So our perception of the flavor of a wine results from the multimodal interaction of the inputs from all the senses with retronasal smell and taste playing dominant roles.

Both books review the five primary tastes — sweet, sour, bitter, salt and umami — detected by the taste buds, with Shepherd going into a bit more depth on the anatomy.  In contrast, Goode emphasizes the aromatic chemistry of the wine, coupling the names of impact compounds with the odors we detect.  Though he has a penchant for presenting the full names of chemical compounds, he moderates them with more taster-friendly references, for example: “Methoxypyrazine:  the most important one is 2-methoxy-3-isobutylpyrazine … is responsible for green, grassy, green pepper aromas” (p. 88).   

But an understanding of what occurs in the brain when wine tasting is not complete without considering the non-sensory influences on our perception of a wine’s flavor.  Each taster’s accumulated memories of wines, especially those consumed regularly, seem to have an impact. Both books mention the work of Donald Wilson of New York University and Richard Stevenson of Macquarie University on how smell objects are formed by synthesizing inputs from our senses with how much we like or dislike the sensations.  Both authors also cite studies that rely on detailed “brain searchery,” much of it performed using Functional Magnetic Resonance Imaging (fMRI), to illuminate where and how our sensory and non-sensory inputs merge. Because the author is himself an active researcher in the field, Shepherd’s book gives a more thorough technical discussion of what was learned and includes numerous drawings of the human head and other images and diagrams.  For example, he elaborates on how an aroma image is formed when the receptors transmit their responses to the olfactory bulb in the brain. 

Goode is clearly comfortable summarizing the results of fMRI studies but keeps it a little less technical.  He does relate concerns about the unnatural environment in which the experiments take place. The subject’s head is immobilized, liquid is squirted in the mouth via a tube all while inside a noisy metal cylinder. “Yes, various brain areas light up…, but their context is hardly a real-world natural setting” (p. 67). Nevertheless, he concludes that “even the limited data obtained so far are highly relevant for wine tasting and are important if we want to provide a robust theoretical basis for the human interaction with wine” (p. 67).

One fMRI experiment that merited mention in both books was by California-based researchers Hilke Plassmann, John O’Doherty, Baba Shiv and Antonio Rangel.  Classified as a study in neuroeconomics, it looked at the impact of price on the perception of taste. People lying in an fMRI tube were given wines whose retail prices had been revealed. When different prices were assigned to the same wine, the scans showed more pleasure was derived when the subjects thought the wine was more expensive.

When it comes to practical advice for the wine taster, Shepherd is no Goode. Not surprisingly, each author’s emphasis is on what he knows best. While Shepherd is clearly more enamored of the science, he lacks Goode’s tasting chops. Shepherd’s idea of a new approach to wine tasting can be summed up in the phrase: “The taste is not in the wine; the taste is created by the brain of the wine taster.” In the appendix, he summarizes a wine-tasting tutorial he had in 2003 with Jean-Claude Berrouet at Château Pétrus. This was his first serious encounter with fine wine and inspired his book.  While the resulting text may be useful to specialists in neuroscience, the advice given to serious wine tasters seems an afterthought, offering little new or practical; for that, Goode is much more effective at delivering the goods. 

Goode proposes a different model: analytic tasting. This method practiced by professional tasters must be done in a controlled environment, free from any distractions which invariably will influence perception.  In contrast, tasting for pleasure is greatly enhanced by shaping the environment with music, lighting, companions and food.  The wine critic should taste wine analytically but also “learn to extrapolate from the artificial setting … to the naturalistic setting in which the readers will be consuming wine…” (p. 202). “I am a firm believer in interrogating the wine …” (p.203) insists Goode.  Training can help, including tasting and developing a vocabulary, he advises. 

While Shepherd’s book speaks with authority on the latest in neuroscience and “brain searchery,” his relative inexperience in wine tasting makes it less suitable for anyone wishing to become a more observant taster.  On the other hand, Goode’s book provides insights from a veteran taster who’s clearly absorbed enough in the science to fashion credible models for tasters at all levels of experience.

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