What Is Terroir?

Recently, I tasted a funky, unfiltered and unsulfured Chenin Blanc from the Catalonia region of northeastern Spain. Chenin Blanc, as you may know, is native to northern France, not Spain, which created an interesting context for the wine. "Whoa," I said. "That's some really Bretty wine," referring to a yeast called Brettanomyces that is often present in unsulfured wines. Bretty-ness, if you will, is considered a flaw by some wine drinkers, myself not included.

A sales rep from Indie Wineries, which imports the wine, just shook his head. "That's not Brett," he said. He went on to explain that Pascaliene Lepeltier, a widely respected master sommelier with a penchant for Chenin Blanc, had told him that this was how the grape variety tasted when it was grown in a certain soil type. To me, this made sense. After all, Lepeltier drinks more Chenin Blanc than some winemakers in the Loire Valley who grow the grape. But there is not one scientific study out there that has proven a connection between soil type and flavor in a wine. In fact, I've heard winemakers profess that it is absolutely untrue that a vine's roots can absorb nutrients from rocks or minerals in the soil. For this reason, people lambaste the common tasting note "minerality," saying it is a new word in the lexicon and has no real meaning. So who is right?

The soil question is part of the ongoing debate over the meaning of the term "terroir." As in: "Yes, this bottle is a particularly good expression of Burgundy's terroir." It's a word you hear, over and over, on the lips of your somm, on the "shelf-talkers" at your local wine shop (you know, those little tags that detail a wine's flavor profiles and point ratings), even at the cheese and charcuterie counter — because terroir, of course, does not apply only to wine. Nevertheless, it is the wine world that places incredible weight on terroir and ties it directly to a wine's value. It is also, within the world of wine, a hotly contested topic that brings to the table issues related to stylistic differences in grape-growing and, above all, winemaking. In addition to the topic of soil, the terroir debate also includes questions about sulfur and yeast.

"No precise English equivalent exists for this quintessentially French term and concept."

You cannot see terroir; it cannot be observed in any tangible way or scientifically calculated. Many scientists out there would probably swear that you cannot even taste it, but master sommeliers around the world would beg to differ. That, of course, is partly what makes terroir so interesting, and wine so captivating of our attention: It cannot be fully understood or charted, yet we can taste a Chardonnay from the Côtes de Beaune and immediately get a sense of the centuries of tradition, soil types and vineyard practices, and that mystical connection between a grape and the place it is grown.

In the most recent edition of the Oxford Companion to Wine, wine expert Jancis Robinson writes, "No precise English equivalent exists for this quintessentially French term and concept." The French led the way in recognizing the unique confluence of land, culture, tradition and climate. Now it is being emulated around the world in wine, spirits and artisanal food products.

For the non-expert, a few broad categories can serve as a useful structure for understanding terroir and the debates surrounding it. Still, it may be best to think about terroir as an open question rather than a thing you can pin down. After all, wine is exciting precisely because it is so full of mystery. Winemakers are often surprised at how a certain vintage turns out 12 months or two years later, when it's finally bottled and showing a completely unexpected personality. And it's also important to consider that terroir, like culture in general, is not static. As in art, music, and literature, the terroir of wine and gastronomy changes over time.

Those three letters you often see on the label of your wine — DOC and AOC — have a lot to do with what we mean by terroir. The appellation system was created in the early 20th century to protect gastronomic traditions and regional identity. In France, right around the time, regional cuisine was being lumped into some kind of a national identity, as soldiers traveling during the First World War got to know the cassoulet of their countrymen in the South, the crepes in the North. Appellations create rules about how a product can be made — which breeds of cows can be used, which grapes, how long a cheese or wine must age, this sort of thing. In addition to wine, this is done with cheese, charcuterie and butter, as well as other products.

France's Appellation d'Origine Controlée (AOC) system was codified in the 1930s to prevent fraud, and is still evolving, as new appellations are created and wines that in some years earn AOC status don't in others (which can become quite political).

Although the current iteration of the appellation system is quite modern, the concept of defining and protecting a region goes back centuries. In Burgundy, for example, it was decreed in the 14^th century that only Pinot Noir and Chardonnay could be grown within the most prized vineyard sites; Gamay was relegated to the southern region of Beaujolais. And the world's first classified wine region was Tokaj, in Hungary, which was proclaimed in the 18^th century to protect the region's sweet wines, which were revered by kings around the world.

Of course, these appellations can also pose problems. On Mount Etna in Sicily, for example, some of the best vineyards, with the oldest vines, are not in the DOC area; winemakers have to make the effort to prove to the governing body that they should be included. This kind of situation happens often, and appellations (or American Viticultural Areas, as they are called in the U.S.) are constantly expanding and contracting, everywhere.

Along with the appellation system is the notion of "typicity," which is the idea that a wine ought to taste like the place it comes from. Along these lines, Rhone Valley Syrah, for example, ought to have black olive notes on the palate.

If you know a little about fermentation, then you might think that yeasts are a simple thing: They consume sugar, which causes fermentation, right? Actually, there are a number of choices that confront winemakers in terms of yeasts. And those choices also involve the terroir.

Historically, all wine was fermented with what's called "ambient" yeasts, which just exist in the environment around us, all the time. In older cellars, there is a buildup of yeasts from over the years, so scarcity is never an issue. Fermentation by ambient yeast is slow, going at a natural pace.

With the modernization of wine in the latter half of the twentieth century, newer cellars and other changes brought on a new practice: using industrial yeasts, made in a laboratory. The practice of inoculating wine with manufactured yeasts is more common in New World wines than Old World and at larger production scales than smaller ones. There are over 100 strains of yeast available for wine fermentation, and they have been selected over time according to various properties and flavors.

Wine drinkers and winemakers alike often have strong opinions about yeasts, for different reasons. For winemakers, using ambient yeasts can pose a risk, because fermentation might not go smoothly or finish entirely. But as well, in some regions, winemakers might consider manufactured yeasts vital to terroir. In Germany, for example, one winemaker told me that using manufactured yeasts allows Riesling to better exhibit its properties as a grape and the properties of the soil it grew in. It's one opinion among many, and natural-wine proponents would disagree, saying that artificial yeasts to some extent obscure the grape's profile and the terroir.

Which brings us back to where all wine essentially comes from: the earth. You could spend forever trying to learn about soil types, what causes them (volcanos and earthquakes, typically), how they impact grape growing and wine flavor. In fact, that is a large part of what wine experts — be they importers, master sommeliers or writers — have to do, because soil type is an important element for terroir.

The most amazing thing about soil, related to winemaking, is how much variation there is not just from one parcel of land to the next (a "parcel" is essentially the smallest unit, a single vineyard), but even within that one parcel, from the bottom of the slope to the top. Soil varies enormously within a region, and this is partly why it is one of the most difficult aspects of terroir to measure.

And it recalls the debate on minerality. Chablis, in France, is probably the best case for examining this issue. Known for producing some of the world's best Chardonnay, the appellation of Chablis has about 13,000 acres of vineyard on what's known as the Kimmeridgian basin. It also has three classifications of wine, each correlated to the soil type. Kimmeridgian soil, which also defines the much-loved white wine of Sancerre (made from Sauvignon Blanc), is based mostly on fossilized oyster shells from the Jurassic Age, as well as limestone and clay. The lowest classification, Petit Chablis, is the highest in elevation and has some limestone. Next, the Chablis (village-level) wine comes from Kimmeridgian limestone soil — this is where the wines start to get age-worthy. Then there are about 40 vineyards designated Premier Cru, and seven Grand Cru vineyards all in one area, where not only are the slopes optimum for ripeness, but there is a greater deposit of fossils. All lovers of Chablis attest to the presence of these oyster shells as well as limestone for the incredibly steely, bright and — how else to call it? — mineral taste of the wines.

Aside from limestone, clay is another important soil type, often considered to lend roundness and richness to a wine (whereas limestone bestows "finesse"). Try a Riesling made from limestone soil beside one made from clay; both may be from the Rheingau and even the same producer, but you will note the difference.

Brevity precludes more in-depth discussion of any of these topics (or others that matter for terroir, like vineyard trellising, vine age, vine clones, or the use of oak), but for those who want to learn more about appellations, typicity, yeast, or soil, the website WineFolly is an excellent resource (as is the site author's new book on wine). But even if your goal is to become a master sommelier, it may never be possible to "know" exactly what terroir is. And what would be the fun, anyway, of knowing wine in an entirely encyclopedic way? Wine is meant to be enjoyed, and while it's interesting to interrogate and debate, the important thing is to drink it, and that means it has to be good.

If there's one thing you take away about terroir, it's this: The more it is taken seriously, by winemakers, sommeliers, wine experts and drinkers, the better our wines will taste, which is, of course, the ultimate goal.

CORRECTION: An earlier version of this article mistakenly referred to Brettanomyces as a bacteria; it is, in fact, a yeast. The author regrets the error.