It doesn't matter which wine producer in Priorat you ask about the secret of the immense quality of the wines of this region, you will always get the same answer: the Llicorella soil that you can taste in the mineral character of the wines. Let's take a closer look. What exactly is this Llicorella soil? What does it do to the vines? And can you really taste the soil in the wine?
Llicorella is the Catalan name for the type of soil in Priorat, which consists mainly of reddish-black slate with small particles of mica quartz, the different layers of soil being filled in by clayey soil.
Slate is a fine-grained, lamellar, metamorphic rock derived from sedimentary rocks composed of clay and/or volcanic ash. That's right...chew on that for a while!
Let's break that down for a moment. Imagine a volcanic environment with a large body of water, such as a lake. The volcanic activity causes volcanic ash particles and other mineral and organic particles to enter the water and settle. This sediment remains when the water dries up over time. At first, this sediment is still clayey, but over the centuries it hardens into rock. Under the influence of heat and pressure in the deeper layers of the earth's crust, the physical and chemical composition of the rock changes. We call this metamorphism (change of form). In the case of slate, the heat and pressure give the rock a kind of lamellar structure. It looks as if the stone consists of lamellae glued together. Pieces of these lamellae crumble and cover the ground as loose rock. Voila...llicorella!
Soil provides the vine with water and nutrients, in the form of ionic minerals (such as phosphate, nitrate, calcium, magnesium, sodium and potassium), in order to grow and produce grapes. Although the ideal soil can vary for different grape varieties, the preferred choice for quality wines is often poor soil that is well drained and poor in nutrients.
If a vine receives ample water and nutrients, this will result in abundant growth of the green parts of the plant (such as leaves and shoots). However, a small water shortage during the growing season can cause the plant to stop its vegetative growth and concentrate on the ripening of the grapes, resulting in better quality grapes.
Ideally, you should grow vines in relatively poor soil, with good drainage, that retains enough water to prevent the plant from drying out in dry periods. And these are precisely the characteristics of Llicorella in Priorat.
The soil of broken slate is poor and retains little water. This forces the roots of the plant to look for water in the deeper layers of clay. In Priorat, vines have been discovered with roots up to 10 metres deep in the earth. The stress (positive in this case) of the search for water causes the grape to grow slowly, giving it character and concentration of flavours. It also results in fewer grapes (in the Priorat, the yield per plant is less than one kilo), which means that the nutrients present have to be distributed among fewer grapes.
The particles of mica quartz in the slate reflect and retain the heat of the sun, boosting the production of sugar in the grapes.
In summary, we can say that the Llicorella in Priorat is an ideal soil type that produces fewer, but better quality grapes. But what about those soil flavours in the wine?
And this is exactly the subject where opinions are divided.
If you ask the winegrowers, you will probably get an affirmative answer, especially in Priorat. In the Old World of wine, the term "terroir" has taken on an almost mythical meaning. Winegrowers who pursue quality wine are almost obliged to make wines that reflect the "terroir" they work with. Nowadays, the term terroir encompasses more than just the soil. It is the sum of natural elements that influence winemaking, such as location, climate, geography, etc. But especially when it comes to the mineral character of a wine (often related to stonelike aromas), one often directly associates this with the minerals in the soil of the vineyard, which are absorbed by the roots. The French even use the expression "Goût de terroir" to describe this phenomenon.
However, from a scientific point of view, a completely different picture prevails. The conclusion of a study on minerality in wine was: "The popular view that we simply taste inorganic minerals transferred from the vineyard soil in wine is not scientifically plausible." (Parr et al., 2018). Professor Jean-Claude Davidian of the Ecole Nationale Supérieure Agronomique in Montpellier, adds: "No one has objectively succeeded in demonstrating a link between the mineral composition of the soil and the taste or smell of the wines". To add that "those who claim to have demonstrated these links are not scientifically reliable".
So while science has yet to find a direct link between soil type and flavour in wine, we cannot deny that many top wines have mineral (and often earthy or stony) aromas. So where do these aromas come from?
Often, these aromas (such as flint or shells) are the result of the formation of organic sulphur compounds during the fermentation of wine. Especially if the juice lacks nitrogen during fermentation and thus becomes somewhat reductive. Interestingly, this nitrogen deficiency often occurs in grapes grown on nitrogen-poor, stony soils, such as Llicorella. And there we have another little hook.
Are the beautiful flavours of wines from Priorat a direct result of the Llicorella soil? No, probably not. At least...not in a direct sense. Does the Llicorella contribute to the world-renowned quality of these wines? It certainly does! The terroir, which certainly includes the microclimate and the location against the costers, provides all the necessary ingredients to produce top quality wines with the typical character of Priorat.
So is terroir a myth or not? Let's put it this way: the most fascinating and complex wines in the world, including the top wines in Priorat, are made by people who consider their terroir to be the main ingredient of their wines. You do the math....!
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