Soil

Soil is composed of a combination of mineral fragments and the local decomposing plant and animal matter. The type of soil in which vines are planted has an impact on the plant’s vigor and the fruit produced. After climate and varietal, most scientists agree that soil type has the next greatest natural influence over characters imparted into a finished wine. However, the direct connection between soil types and the attributes they contribute to wine remains a source of endless and entertaining debate, and more research is needed on this matter.

Several soil classification systems exist, however soil types are commonly grouped according to a combination of the type of minerals found and the size of their particles.

Most soils are a blend of stone, sand, silt and fine clay particles. The size of the fragments is important because of the connection to water retaining properties and drainage.

Looser gravel based soils allow water to run off more freely after rainfall, so roots must actively seek more widespread growth to ensure enough water is available for the plant to survive. Many viticulturists believe that stresses associated with poor water retention help improve the quality of the fruit.

Medium loamy typed soils contain a more equal balance of larger sands, smaller silts and fine clays. Loamy soils retain moisture but also drain well so that sufficient air can reach the root system.

Soils primarily composed of clay retain water and nutrients extremely well. Because clay based soils can easily become tightly packed, they tend to drain poorly and air has difficulty penetrating to the root system.