Understanding wine tasting through “brain searchery”— the tale from two books
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? The sensory and non-sensory contributions to our enjoyment of this beverage 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 Yearat the 2017 Louis Roederer International Wine Writers’ Awards. While the stated objective, to offer a new approach to wine tasting, and much of the material covered are the same, the approach, emphasis and utility of each book differ as markedly as the author’s background.
Acknowledging that there is still much to be discovered, Shepherd and Goode take us through the basics of how our senses work in combination with each other. All five senses, not just the chemical ones which are smell and taste, 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 experience when breathing in, triggers the smell receptors in the nose. With the first sip, the wine blends with saliva and activates retronasal olfaction stimulating receptors inside the mouth and throat when breathing out. Different areas of the mouth contain sensors that react to touch, pressure, temperature, and pain, and create the mouthfeel of the wine. Taste buds house receptors that 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 a dominant role.
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 goes on 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 drunk 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. Subjects laying 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 phase: the taste is not in the wine; the taste is created by the brain of the wine taster.” (p. 1) 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 seeking a summary of knowledge gained to date, the advice given to serious wine tasters seems like an afterthought, offering little new or practical. For that, Goode is much more effective at delivering the goods.
Having presented the state of the science for the edification of the taster, Goode proposes a different model for wine tasting based on the objective. Analytic tasting, the type 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. I would add tasting mindfully and taking notes, especially when sampling better bottles.
While Shepherd’s book speaks with authority on the state of the art 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 has clearly absorbed enough of the science to fashion credible models for tasters at all levels of experience.
Neal Hulkower is a mathematician and an oenophile living in McMinnville, Oregon. His wine writing has appeared in a wide range of academic and popular publications including the Journal of Wine Research, the Journal of Wine Economics, Oregon Wine Press, Practical Winery & Vineyard, Wine Press Northwest, and The World of Fine Wine. Occasionally, he can be found pouring quintessential Pinot noir at the top of the Dundee Hills.