The Wine Aroma Wheel

Certain Cabernet Sauvignon or Sauvignon Blanc wines reveal notes of green bell pepper, for example, not because peppers have been thrown into the fermenting vat with the grapes, but because the wines, like the peppers, contain the flavor compound isobutyl-methoxypyrazine (IBMP). The related compound isopropyl-methoxypyrazine (IPMP) brings on the canned asparagus taste found in some wines. Wines that undergo malolactic fermentation, a secondary process in which bacteria help break down the wine's malic acid into softer lactic acid, often show signs of diacetyl, which translates into the buttery, nutty or toasty flavors common (and sometimes a bit too pushy) in many New World Chardonnays. The tobacco note will make a wine scientist give a knowing nod: “yup, that's megastigmatrienone again, doing what it does best.”

The science here is handy not because we need to memorize all these formulaic terms, but because it shows us that wines have aroma and flavor notes for perfectly explainable scientific reasons. Using the science, Ann C. Noble and her colleagues at the University of California at Davis have over the years refined a system of descriptive wine notes that they have incorporated into an “Aroma Wheel.” The wheel, which is available in a number of languages and also in a sparkling wine version, is color coded and sensibly laminated (else I imagine it would quickly begin to give off aroma notes of its own). The wheel, which is about the size of one of those individual pizzas, is six dollars and is available at www.winearomawheel.com.

“The requirements for words to be included in the wheel,” the instructions indicate, “are that the terms are specific and analytical and not hedonic or the result of an integrated or judgmental approach. 'Floral' is a general but analytical descriptive term, whereas 'fragrant,' 'elegant,' or 'harmonious' are either imprecise and vague (fragrant) or hedonic and judgmental (elegant and harmonious).” The wheel sticks carefully to that which we can taste and smell, avoiding questions of color, clarity, body, astringency, texture, viscosity, and other wine qualities we see or feel.

The wheel is arranged in three concentric circles, ranging from the most general in the center to more specific manifestations at the edges. As an example, the large category called “Fruity” breaks down into six sub-categories: “Citrus,” “Berry,” “Tree Fruit,” “Tropical Fruit,” “Dried and Cooked Fruit,” and “other.” Each of these categories is subdivided into specific fruit notes; “Tree Fruit” includes cherry, apricot, peach, and apple. The “Herbaceous/Vegetative” category breaks down into “Fresh,” Canned/Cooked,” and “Dried” subcategories; our bell pepper (which we now know is IBMP) shares the “Fresh” category with cut green grass, eucalyptus and mint, while the asparagus (IPMP) shares the “Canned/Cooked” category with green bean, green olive, black olive and artichoke. The interesting “Dried” category includes hay/straw (one of my absolute favorites) and tea.

Of course, not every wine note represents something we can eat or drink; “Microbiological – Lactic – Sweaty” might not be so pleasant (unless it is your own sweat which, admit it, you find inspirational), while the “Chemical – Pungent – Ethyl Acetate” track equates to the beloved smell of nail polish remover (an indication that the wine has been spoiled by vinegar bacteria). Among the “Woody” notes, the “Resinous” subgroup includes vanilla, cedar, oak and tobacco, the “Phenolics” include bacon and that medicinal smell, “Burned” notes include coffee, burnt toast and smoky; most of these woody notes achieve good frequency in wine reviews.

Professor Noble and company do not suggest we form-fit every impression into conformance with the wheel. “These terms are NOT the only terms that can be used to describe wines,” the instructions indicate, “but represent ones that are often encountered.” I suspect that my own note, “baseball mitt,” which specifically is the taste of the leather string on the mitt that I have been chewing since I have nothing better to do because I have been placed out in right field because no one hits there, might fit somewhere in the “Resinous” group. “Yum,” “Ethereal,” and all those other subjective terms are not on the wheel, but that hardly means you must abandon them entirely. Think of the wheel as an authoritative “consult me first” resource and you will be on the right track. With many wines, even those of quality, the wheel ought to cover most bases quite nicely.