“Age is irrelevant,” tweeted a fellow wine professional yesterday, in the context of a discussion of vineyard soil quality. While I applaud her lack of prejudice, and while the age of a piece of land (by land age I refer to the epoch in which the sub-soils were formed) is not linearly correlated with soil characteristics— let alone wine quality—the age of a soil can tell us a lot.

The Fanciulle Vini project was born of curiosity: how do Sangiovese wines grown on the different subsoils of Tuscany taste? In the first phase of the project we identified 12 subsoils planted with vines, as well as wine estates on each type who were willing to sell us grapes. Now that we are three vintages in, we can taste, in the different wines—beyond their typical Sangiovese aromas and tastes—what differs from wine to wine. Since we have tried to reduce other variables as much as possible, these differences are due in large part to their terrain of origin.

Geologists did not necessarily like the idea of this project. “One can’t generalise—Tuscan land is too varied!” they argued. Viticulturalists didn’t like it either. “There are so many other factors influencing the wine—the vineyard’s microclimate, the clone”–they insisted on the primacy of the clone. Many wine estates themselves didn’t like my project. “What matters is the oenologist,” they said. “We already know our land.” 

One geologist said it was no use trying to characterise or classify soils. He told me about his doctoral thesis on the different subsoil types in Montalcino. It showed that although the Brunello appellation covered all vineyards within county lines, vineyard land characteristics and quality varied widely. He got the highest grade possible but the thesis was never published—it was buried by his thesis supervisor, a sometime consultant to a handful of important estates with no interest in revealing that any of their vineyards were planted on atypical soils of questionable quality.

What is a lower-quality soil, even? Our ancestors showed us part of the answer. They planted olive trees on hill-tops, where drainage and aeration are assured. They planted vines on hillsides, where they would be protected from the coldest air currents but still well drained. And in the valleys, where the topsoil was deep and fertile, they planted wheat and hay. In the 1980s, when prices for Tuscan wines rose faster than the consumer’s ability to distinguish good from mediocre, wine estates planted vines wherever they could. Today, we have famous appellations with vines planted, yes, on great soils but also on soils where, until recently, wheat was grown, or livestock raised. This happened to a much lesser extent in Burgundy, where there is a decades- if not centuries-old consensus as to which sub-soils produce the best wines and where wine and land prices are highly correlated to this consensus. 

Why don’t we in Tuscany want to look more carefully at our sub-soils, develop our understanding of what each contributes to the taste of a wine and work towards classifying our vineyard land (not along political divisions like county but on the basis of physical and chemical characteristics) in an absolute sense? Two main reasons have emerged over the past three years, the obvious one being that wine estates are, understandably, afraid they won’t have any land that ends up in the top categories. Another, more subtle reason, is that the impact of sub-soil is the hardest to gauge. The impact of vintage, say, is easier to recognise: think of the the difference between a riper, richer wine made in a sunny year and a thin, bitter wine made in a rainier one. Cellar effects, likewise, are easy to spot: the use of oak, of long macerations, of a more-or-less hands-on approach overall have relatively straightforward signatures in the wines. But subsoil? Who’s to say?

A notion among wine lovers is that limestone-rich soils offer some of the best land for growing vines. Where does this idea come from? Some of the most prized vineyards in the world are planted on limestone, of course, such as in the villages of the Côte de Nuits. But what does limestone do to vines, to grapes, to wine? I would describe its impact as umami, namely, that limestone (i.e., basic) soils—other factors such as grape varietal, vintage and cellar approach being equal–tend to produce grapes with a sweet-and-savory taste that lingers in the back of your throat. Subsoils impact a wine’s tannins, and tannins determine texture. Persistence is a factor of acidity, and while acidity is a factor of weather, of course, there is a rapport (inverse, by the way) between the acidity of wines and the soils the grapes were grown on.

Where is the limestone in Tuscany? In the blue spots on the map, which is where age comes in. Calcareous soils are made up of deposits from living things, and thus accumulated in periods when life—especially ocean life—flourished, because the ocean is full of living, dying organisms. Calcareous soils were formed when warm (life-giving), shallow (so concentrated with living things) oceans covered Italy (and France), which happens to have been a very long time ago. Those lovely blues on the map are soils that date back 60-90 million years, and are therefore much “older” than most of the other terrains in Tuscany. Good subsoils are calcareous subsoils, and calcareous subsoils are old.

My arguments are imprecise, premature even—I know. But I am compelled to go down the road of the soil-taste connection, to delve further into the mystery of wine.