Chinese author Gus Zhu MW Zhu has given us another, gentler place to turn for answers when pondering what we are tasting and why. 

By Neal Hulkower. THE WORLD OF FINE WINE

Image by Shutterstock.

Dr Neal D Hulkower reviews Behind the Glass: The Chemical & Sensorial Terroir of Wine Tastingby Gus Zhu MW.

In the late 1960s and ’70s, when I first waded into the world of fine wine, I don’t recall there being any books or periodicals that offered a novice nontechnical descriptions of what creates the aromas and flavors in a wine and how our senses interpret them. And honestly, I wasn’t looking for any. I was content to explore wine purely hedonistically as a welcome respite from my very left-brained graduate studies. The last thing I was thinking about when sipping a claret or Spätlese was its chemical composition and which part of my tongue or nasal receptors were being stimulated.

But over the decades, familiarity bred curiosity—not just in me, but also in the folks I host in a tasting room at the top of the Dundee Hills in Oregon’s Willamette Valley. For example, I was recently asked about a Pinot Noir rosé, “What am I tasting?” I demurred. Falling back on what I had learned from Neuroenology: How the Brain Creates the Taste of Wine (Columbia University Press, 2016), 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, I pointed out that there was no way I could perceive what the questioner was tasting. Each of the authors has the scientific chops to steer us through the paths that our senses go through to create the flavors we detect. Goode’s significantly greater experience in the wine world gives him the edge in offering practical advice to the taster.

There is now a new source from which to learn more about what makes wine so enticing. Behind the Glass: The Chemical & Sensorial Terroir of Wine Tasting by Gus Zhu MW is the latest to offer insights to the neophyte enophile, addressing questions in a less technical way than Shepherd and Goode. (Gus) Jian Zhu is well qualified to take on the task of guiding the reader through the complex (and still not completely understood) web of interactions one experiences when tasting. In addition to becoming the first Chinese Master of Wine in 2019, Zhu is coauthor of a review paper entitled “A Quarter Century of Wine Pigment Discovery,” which appeared the same year in the Journal of the Science of Food and Agriculture, and he is a research and development scientist at Cork Supply and Tonnellerie Ô, both in Benicia, California, south of Napa Valley. He lists as specialties wine pigments and sensory evaluation. Each plays a major role in his exposition.

In the introduction, Zhu’s motivation for writing the book is revealed: “I have often been asked to explain the science behind why a glass of wine tastes the way it does.” It boils down to the complex chemistry, which is understood to some degree, and to our senses, which “are among the least understood subjects in the scientific world.” He concludes as I had: “The same glass of wine is perceived in different ways by different people” (p.1).

To structure his presentation, Zhu adopts “chemical terroir” and “sensory terroir” as his organizing principles. “The chemical terroir of wine tasting is about the chemical composition of the wine itself that contributes to the sensory profile. Every glass of wine has a unique matrix of chemical components that forms a terroir of its own,” he explains. On the other hand, “The sensorial terroir of wine tasting refers to human perceptions of the chemical compounds in wine” (p.3). Throughout the text, he deftly introduces the appropriate concept or term, though not always defining the latter at first use.

While the intent of the book is clearly pedagogical, Zhu assures us that “as this is not a textbook (and there is no exam) there is no need to have foundational knowledge of chemistry and sensory-related fields” (p.4). While this is true, the subject matter necessarily requires the use of chemical names and other scientific terms that may give the reader pause. The goal is to get on a first-name basis with terms like phenolics, anthocyanins, and terpenoids, while also making accommodation with phenylacetaldehyde, 2-isopropyl-3-methoxypyrazine, and other tongue twisters, but not to pass a PhD-qualifying examination in chemistry or enology. The illustrations lend useful support for the text.