🪨 Schist

Schist is a layered rock that splits easily into thin plates. It forms from clay and other sedimentary rocks under pressure and heat, and so consists of dense layers. Schist can be grey, blue, black or brown.

For grapes this soil is special. Vine roots go between the layers deep into the ground, searching for water and nutrients. The soil is poor, and the vine struggles to survive, so berries are few but concentrated. Schist holds heat well: it warms by day and gives the warmth back to the vine at night. It also lets water drain freely.

The best-known example is the Douro valley in Portugal, especially the Upper Douro. There, grapes for Port and dry red wines grow on schist slopes. Similar soils exist in the Mosel, the Rhône and Priorat. Schist belongs to the general idea of soil. A related rock is shale, softer and thinly layered. Wines from schist soils are often described as mineral.