Do molecules from the soil directly affect the flavors of wine or food?

I am reading the book Tasting French Terroir: The History of an Idea by Thomas Parker. The topic of this book is the study of French literary, culinary, and agricultural texts, mainly from the 16th through 19th centuries. The focus of the book is limited to these texts and how they displayed varying attitudes over time towards the value of local qualities -- terroir -- in food and wine. Parker is concerned primarily with the way that the development of the concept of terroir played a role in the development of French national identity and language.

In reading Tasting French Terroir, I felt as if the author never addressed the question of whether there was objectively and measurably a taste imparted to wine by the minerals and other substances in the soil where the grapes were grown. The writers whose texts he analysed believed in such a taste, and that’s the only thing that concerns him. However, I was curious so I looked it up a little bit.

No one disputes that wines from different vineyards have varied flavor. However, experts discuss at great length which wines reflect strong characteristics arising from local differences in soil, cultivation, and climate, and which wines display more less of this so-called taste of terroir/goût de terroir.

Any such discussion ultimately depends on a key question: In actuality are humans actually able to discriminate soil flavors in wine? To quote the much-respected food chemistry writer Harold McGee:

“It’s hard to have a conversation about wine these days without hearing the French word terroir. Derived from a Latin root meaning ‘earth,’ terroir describes the relationship between a wine and the specific place that it comes from. For example, many will say the characteristic minerality of wines from Chablis comes from the limestone beds beneath the vineyards (although, when pressed, they generally admit that they’ve never actually tasted limestone). The idea that one can taste the earth in a wine is appealing, a welcome link to nature and place in a delocalized world; it has also become a rallying cry in an increasingly sharp debate over the direction of modern winemaking. The trouble is, it’s not true.”

Ultimately, McGee agrees in a way with the central idea of Tasting French Terroir: he states that not just the minerals in the soil (or as he calls them, “rocks”) provide locally made wines their distinctive characteristics, but that the entire process of growth and winemaking combine to provide them. McGee says:

“If rocks were the key to the flavor of ‘somewhereness,’ then it would be simple to counterfeit terroir with a few mineral saltshakers. But the essence of wine is more elusive than that, and far richer. ... ‘Somewhereness’ is given its meaning by ‘someoneness’: in our time, by the terroirists who are working hard to discover and capture in a bottle the difference that place can make.” (from Harold McGee, “TalkDirt to Me,” New York Times, May 6, 2007.

Food writer Robert Hass wrote about the question in 2008:

“…terroir in its current use has taken on a new importance.  The expanding employment of vineyard designations on New World wine labels is a sign of our current efforts to give specific ‘somewhereness’ to both varietally labeled wines and blends. We are using terroir in a positive sense as a tool to emphasize a wine's taste characteristics determined by soils and climate as opposed to those specific to a given grape varietal or those which come from cellar manipulations. Cellar manipulations, and the sameness that these can produce in wines from different areas (and even different grapes), are coming more and more under fire from a growing number of consumers and press as a misstep in the search for more ‘natural’ wines.” (from “Terroir, Then and Now” by Robert Hass)

The idea of goût de terroir is more broadly applied to many other foodstuffs, and the question of which local characteristics contribute to local flavor distinctions can also be asked more broadly. “Artisanal crops for which terroir is studied include wine, coffee, tobacco, chocolate, chili peppers, hops, agave (for making tequila and mezcal), tomatoes, heritage wheat, maple syrup, tea, and marijuana.” The ideal of special local flavors extends even to chickens grown in specific places, like poulet de Bresse from France; oysters from varying seacoasts, cheeses, mushrooms, and so forth. (Quote from Wikipedia.)

Discussions of goût de terroir relate to the general interest in eating locally grown foods. Products valued for their regionally-unique flavors are often shipped great distances and valued well beyond their region of origin. The reasons for eating locally go well beyond the question of discriminating such tastes.

My more conventional book review of Tasting French Terroir will deal with the questions that Parker did study rather than with this one which he did not discuss. I’m writing the review for Repast, the journal of the Ann Arbor Culinary Historians.