How Terroir Effects Wine
Terroir is a term used in winemaking to denote the special characteristics that the geography, geology and climate of the vineyard bestow upon the wine, contributing to its specific personality. The concept of terroir ultimately lends itself to the idea that wines from a particular region and winery are unique and are incapable of being reproduced anywhere else. Terroir not only embraces the dirt itself (terre in French), but the subsoil beneath it, water drainage, the way it interacts with sunlight, the slope of the land and many other micro environmental differences that are commonly reflected in the character of the wines from each region.
Many processes during winemaking can have an effect to either enhance or downplay the expression of terroir within the wine. Human activity has a large impact on terroir, as the specific conditions and processes that the grapes are harvested in, and the wine is made in, is influenced by the preferences of the winemaker on whether they want to preserve the terroir. Irrigation, pruning, and time of harvest are all aspects of terroir in the vineyard. Once the grapes hit the winery, the type of barrel, yeast, temperature, fining agents and fermentation time and aging are all aspects that can have an effect on the expression of terroir in the wine.
The importance of the preservation of terroir depends on the culture of a particular wine region. As an example, in France, it is said that the role of the winemaker is to enhance the expression of the terroir. As such, it is a compliment in France to tell a winemaker that his wine has terroir (or goût de terroir), meaning that they can taste where it was produced. In fact, the term in French for winemaker, “vigneron” appropriately translates to wine-grower. Many French wine labels emphasize the region or vineyard rather than the grape varietal, highlighting the fact that they believe terroir to be the wine’s dominant influence.
The idea of terroir is quite a controversial one. Originally it was thought to be due to differences in the chemical compositions in the soil. Some say that they can taste when I wine has a specific mineral in it, due to its high concentration in the soil. Botony, or the scientific study of plants, renders this argument rather moot, as, biologically; this is not how plants interact with their soils. A more progressive view takes the stance that terroir is not due to subsoil structure, but rather to drainage. Plant reproduction is based on the principle that if their environmental conditions are good, the plants will have vegetative growth. If the conditions are bad however, they will reproduce sexually, meaning the production of fruit. While this seems a little counterintuitive, viticulturalists aim to create an environment where they are harsh enough on their vines so that the production of fruit is emphasized, though not too restricting as to cause a mineral deficit, which would sabotage the ripening of the fruit. Restricting their environment causes the roots to grow deeper and more laterally in search of nutrients. The deeper the roots grow, the more constant their environment becomes with a reliable source of mineral and water supply. Having the deepest roots, this explains why old vines produce some of the best wine.