Keys to Understanding How Soil Affects Wine

Soil affects grape vines, and therefore wine, in myriad ways. We’ve written extensively on the topic, from the time we highlighted Pedro Parra, the terroir hunter, to when we focused on volcanic soil, to the deep dive we did on all soil. The topic is endlessly complex!

However, there are three key concepts that can help you wrap your head around the interplay between soil and vines: heat retention, water drainage, and mineral content. 

Heat retention refers to how much the soil affects the temperature in the vineyard. Some soils, such as the slate schist of Priorat - known locally as “llicorella” - absorb so much heat that they stay warm throughout the night. This high average temperature leads directly to higher ripeness in the grapes, meaning higher alcohol and richness of both texture and flavor, especially fruit notes.

Soils that drain water well tend to also be porous, which allows the vines to send longer roots in search of nutrients. Vines in these soil types tend to create grapes with balancing acid, even in hot climates. In cool climates, these soils amplify the natural freshness caused by lower temperatures.

Finally, we come to mineral content. Often, literature on soil mineral content makes it sound like vines act as mechanisms to transport minerals from the soil and deposit them inside the grapes. This type of one to one explanation sounds right, but doesn’t account for the fact that vines are organisms, not mechanisms. Think about it this way: why do people need minerals in our diet? Because they change our health. Same for vines. Certain types of minerals in high concentration change the health of the vine in specific ways, which then has predictable impacts on the textures, aromas and flavors of the resulting wines.