Vitis vinifera Explained
What Is a Grape Variety?
Riesling, Merlot, Sangiovese: behind each name lies its own plant with its own genetic makeup. This stop explains what distinguishes a grape variety from a clone or a crossing, and why nearly all of the world's viticulture traces back to a single species.
A Variety Is a Genetic Fingerprint
A grape variety isn't a flavor category. It's a distinct plant with its own genetic blueprint. That's why winemakers don't propagate it from seed. A seed would produce a new, unpredictable mix of the parent plants' traits. Instead, growers cut a shoot, root it, and graft it onto a hardy rootstock. This creates a genetically identical offshoot of the mother plant. Every Riesling vine in the world is related in this way to the very first Riesling plant ever grown, almost like a living copy passed down across centuries. In the past, varieties were distinguished only by leaf shape, bunch structure, and growth habit. This science is called ampelography, and it demands a very well-trained eye. Some ampelographers could reliably tell closely related varieties like Sauvignon Blanc and Sauvignon Gris apart just from tiny differences in leaf veining, long before any gene lab existed.
Today, genetics does this work more reliably than the naked eye ever could. A laboratory at the University of California, Davis, revealed something astonishing in the 1990s. Three varieties with completely different names turned out to be genetically identical: Zinfandel from the USA, Primitivo from southern Italy, and Crljenak Kaštelanski from the Croatian coast. For decades, winemakers had argued over this grape's true origin without knowing the answer. A single DNA test settled the debate within weeks. Genetics always trumps legend. Such genetic surprises aren't the exception: for many other storied varieties, it later emerged that centuries-old family legends about their origins were simply invented.
Nearly All Viticulture Rests on One Species
Botanically, almost all known wine grape varieties belong to one and the same species. It's called Vitis vinifera, the European grapevine. Think of it like dog breeds: wildly different appearances, but one shared species underneath. Cabernet Sauvignon, Chardonnay, and Sangiovese are therefore botanically more closely related than their very different flavors might suggest. Their shared homeland lies in the Mediterranean and the Near East. From there, viticulture spread over millennia to the world's most remote corners. Yet within this single species lie enormous differences, roughly the way a Chihuahua and a Great Dane, despite sharing a species, seem to have almost nothing in common.
Alongside this, other vine species play supporting roles in winegrowing. North American Vitis labrusca, for instance, is behind the Concord variety. It carries a pronounced strawberry-candy aroma, a note connoisseurs call "foxy." This species is mostly processed into juice, less often into wine. Crossings between vinifera and American wild vines, meanwhile, yield hardy varieties suited to cold or damp regions—more on that at the next stop of this journey. In the US and Canada, some winemakers deliberately plant such robust hybrid varieties in places where harsh winters would regularly kill pure Vitis vinifera.
A Thousand Names, But Far Fewer True Varieties
Databases list eight to ten thousand grape names worldwide. But many of these simply describe the same plant under a different regional nickname. The standard reference work "Wine Grapes" by Jancis Robinson, Julia Harding, and José Vouillamoz drew on years of genetic analysis. In the end, the authors described roughly 1,368 genuinely distinguishable varieties in detail. Of these, by their estimate, only a portion—around seven hundred varieties—are still grown to any meaningful extent. For comparison: most vegetables at the supermarket exist worldwide in only a handful of common cultivated forms, whereas viticulture, with its thousands of names, remains far more diverse.
The rest survive in isolated old vineyards, in gene banks, or only in old books. Some varieties today exist as just a few hundred vines worldwide. A handful of international varieties, such as Cabernet Sauvignon or Chardonnay, grow on almost every continent by contrast. They ripen reliably and are known worldwide. This very tension between a few global varieties and thousands of local treasures runs through the entire journey this stop opens up. Anyone who encounters a completely unfamiliar variety in the glass while traveling is often holding a small surviving fragment of what was once a far greater diversity.
Why the Name Doesn't Explain Everything
The variety sets a rough framework. Riesling almost always brings plenty of acidity. Cabernet Sauvignon almost always brings firm tannins. But how a wine actually tastes in the end depends just as much on climate, soil, and the choices made in the cellar. One and the same variety can turn out cool and lean. It can just as easily turn out warm and powerful, with no change to its genetic makeup at all. Even experienced tasters therefore regularly mistake a cool-climate wine from a warm-climate variety for a warm-climate wine from what's normally a cool-climate variety.
That's exactly what the coming stops on this journey explore. First comes the question of how new varieties arise in the first place. This happens through deliberate crossing of two parents. It happens through random mutation into a clone. And nowadays it happens through deliberate efforts to make vines more resistant to fungal diseases. Once you understand these connections, you read a wine label with completely different eyes, because variety name, origin, and winemaking suddenly feel like pieces of one shared puzzle.