As with any plant, the soil that a vine is planted in will influence its growth, health, vigor, and production. Most winemakers prefer well-draining, rather infertile soils for their vines. This may seem counter-intuitive, but in order to make quality wines it is imperative. The main component to the final wine's quality is the vine's yield of grapes. The viticulturalist seeks to minimize the nutrition, both of water and minerals, in order to stress the vines. This stress causes the vines to produce fewer, more concentrated grapes making for greater flavor and aroma complexity, as well as sugar and acid balance.
- By planting in well-drained soils, the vines pull from a more reduced and constant supply of water. Therefore the vines are rarely inundated with water, which prevents over-swelling of the grapes that would make for diluted wines. This water stress encourages the vine's roots to dig deep and spread out in order to access the deeper, purer underground water sources.
- The deeper the roots reach, the more varied soil layers they will be tapping water from, increasing the complexity of the grape and wine composition exponentially.
- The soil color, stones and rocks influence how well the soil will retain heat - which is especially crucial for cooler climate viticulture because it aids in ripening. The darker the earth, and the more stones present, the greater the heat retention. In some regions low on sun, the stones are also used to reflect the sunlight onto the vine!
- The soil's acidity will also be reflected in the wines.
Viticulturalists and winemakers have long observed that the soil also contributes to the aroma and flavor profiles, as well as the structure and even longevity, of a wine- and this concept is one of the most important contributing factors which lead to the notion of "terroir". Terroir is the French term now used internationally to indicate not only the landscape and soil composition of a vineyard, but also factoring in the influences of the local climate, the mesoclimate (that of a specific vineyard plot, which can vary within a few yards), sunshine days, and prevailing winds. In true French romanticism, the winemaker will often subscribe some other factor to his terroir as being the unique differentiating attribute of his vineyard, making his wines impossible to replicate anywhere else. This notion is unquestioningly espoused in most of Europe, especially in France, but is practically absent in most of the New World winemaking lexicons. Only recently have these winemakers begun to embrace the effects of the terroir on the wines produced. New World winemakers were so caught up in displaying their personal styles through their wines, but are now beginning to let the wines be "made in the vineyard" with nature's hand playing the most crucial role in a wine's personality.