What Is Terroir? Soil, Climate and the Human Touch

Terroir is the idea that a wine carries the character of the place it was grown: its soil, its climate, the slope of the vineyard and the way local people farm the vines and make the wine. It is a big part of why a Chardonnay from Chablis differs from one grown in California, and why many European labels name places rather than grapes. Here is what the word officially means, how each part works, real examples, and why some scientists think the idea is overstated.

The official definition

Terroir is a French word that wine people used for a long time without an agreed meaning. In 2010 the International Organisation of Vine and Wine (OIV) adopted one: Resolution OIV/VITI 333/2010, passed at its General Assembly in Tbilisi, Georgia, on June 25, 2010.

In our paraphrase, the OIV defines vitivinicultural terroir as an area where a shared body of knowledge builds up about how the local physical and biological environment interacts with the way vines are grown and wine is made, giving the wines from that area distinctive characteristics. The resolution lists what that environment includes: soil, topography, climate, landscape and biodiversity.

Three things stand out:

1. Terroir is an area, not a single factor.
2. People are part of it. “Applied vitivinicultural practices” and “collective knowledge” mean the local way of growing and making wine counts, not only nature.
3. It is descriptive. The resolution says the definition is for descriptive use and warns against confusing it with the legal definition of a Geographical Indication, such as an appellation.

The OIV said in a 2024 retrospective that its experts needed almost ten years of discussion to agree on the wording. The same article, drawing on former OIV Viticulture Commission president Benjamin Bois, traces how the word’s meaning shifted: from a 12th-century term for an agricultural area to the 20th-century idea that a place’s many natural and human factors shape the quality of what it produces.

The parts of terroir

Factor	What it covers	Why it matters in the glass
Climate	Temperature, sun, rain, wind, frost	Sets how ripe grapes get: more sugar and alcohol in warm places, more acidity in cool ones
Soil and rock	Drainage, water holding, depth, fertility	Controls how much water and vigor the vine has, which affects ripening and concentration
Topography	Slope, aspect (direction it faces), altitude	Steep, sun-facing slopes ripen grapes in cool regions; altitude keeps nights cool
Landscape and biodiversity	Rivers, forests, plants, microbes	Rivers and lakes moderate temperature; microbes take part in fermentation
People	Grape choice, pruning, harvest date, winemaking traditions	Local know-how decides which grapes grow where and how the wine is made

The right-hand column is our plain-English summary of how these factors usually work, not a quote from the OIV.

Terroir in action: four examples

Chablis: a famous soil

Chablis, in northern Burgundy, is the textbook example of soil as terroir. The Bourgogne wine board says the Chablis, Premier Cru and Grand Cru vineyards are planted mainly on Kimmeridgian marl, a soft limestone and clay laid down more than 150 million years ago and full of tiny fossil oysters. Petit Chablis grows mostly on the harder, younger Portlandian limestone on the plateaus.

That split lines up with the appellation levels: the top three on Kimmeridgian, the entry level mostly on Portlandian. Burgundy also uses the word climat for a named vineyard plot recognized over centuries, a very local form of terroir. Our Chablis wine guide covers the four levels and the seven Grand Cru climats.

The Mosel: slope and slate

In Germany’s Mosel, the slope may matter as much as the soil. Wines of Germany says about half of the region’s vineyards are steep or terraced sites with gradients above 30 degrees, some as steep as 70 degrees, and that the steep sites are on Devonian slate. Elsewhere in the valley the soils change: clayish slate and greywacke in the lower Mosel, sand and gravel on the flats, and shell limestone in the upper Mosel. “Slate and Riesling dominate the vineyards,” the board says, with 5,156 hectares of Riesling. Our German wine guide has more.

Muscadet: rock types written into the rules

Muscadet, near Nantes in the Loire Valley, shows how terroir ends up in law. The 2025 rulebook for Muscadet Sèvre et Maine recognizes seven village crus and describes the rock under each: coarse-grained granite in Clisson, gabbro in Gorges, gneiss with veins of green rock in Goulaine, orthogneiss and granodiorite in Château-Thébaud. It also links each one to a style, from Clisson’s rich, fruity wines to Château-Thébaud’s fine, taut ones with freshness and minerality.

The same rulebook shows the human side of terroir. The local sur lie method, leaving the wine on its yeast lees through the winter, is described as a know-how born from growers’ habit of keeping a barrel of their best wine on its lees for family celebrations. See our Muscadet guide.

Barolo: named vineyard areas

Italy has its own version. In Barolo, official named areas (MGAs) let a label say exactly which hillside the Nebbiolo came from.

Is terroir real? The debate

Few wine ideas are argued about more.

The skeptics. Mark A. Matthews, Professor of Viticulture at UC Davis, wrote Terroir and Other Myths of Winegrowing (University of California Press, 2016). His publisher describes it as applying a scientist’s skepticism to widely held beliefs about winegrowing, including whether terroir is mainly a marketing idea. The OIV itself acknowledges the tension: its honorary president Peter Hayes notes that because the term is so widely used in marketing and regional policy, it needs ongoing explanation, and the OIV’s 2024 article cites a 2020 scholar, Leturcq, who calls terroir an ahistorical concept.

The defenders. Wine Spectator columnist Matt Kramer answered Matthews in April 2016. In his view, the book leans on “scientism,” a trust in data alone; he argues that anyone can taste the difference between two well-made wines from different sites, and that soil plays an informing role, more clearly in some sites than others.

The new science. Research has added new angles. A 2014 study in PNAS by Nicholas Bokulich, David Mills and colleagues profiled the fungi and bacteria living on wine grapes and found that region, vineyard site and grape variety all shape those communities, which also tracked local climate. The authors proposed a “microbial terroir” as one factor in regional differences.

Where we land: in our view, the strongest evidence for terroir is climate and water, and the weakest claims are that you can taste a specific rock. When a wine writer says a Chablis “tastes of oyster shells,” we’d read it as a useful description, not a chemical fact. Still, the fact that places like Chablis, the Mosel and Muscadet keep producing recognizably different wines from the same grapes is hard to dismiss.

How to taste terroir yourself

You can’t taste soil directly, but you can compare places:

1. Hold the grape constant. Open two Chardonnays, one from Chablis and one from California, or two Rieslings from different German regions.
2. Compare the same producer’s sites. Many Burgundy and Barolo producers make several single-vineyard wines from the same vintage. In our view, this is the clearest way to see terroir.
3. Compare vintages. The same vineyard in a hot year and a cool year shows how much climate matters.
4. Read the label for place names. In Europe, the smaller the named place, the more the producer is claiming that terroir matters.

For a map of where these places are, see our guide to the wine regions of the world.

Note: Terroir isn’t a quality score. A distinctive place can make simple wine, and a great winemaker can make excellent wine almost anywhere. Terroir explains difference, not price.