The array of flavours contained in wine is not just down to the grape variety, the location of the vineyard and the type of wine press used; it also comes from the soil and thus the geological subsurface. Rock and soil could be described as the primary sources of the terroir and thus, the wine itself.

Terroir

Terroir comprises all the natural factors of a landscape that influence the characteristics of the vine seedlings cultivated there.

In 2010, the OIV (International Organisation of Wine and Vine) defined the term “terroir” as follows: “Terroir includes specific soil, topography, climate, landscape characteristics and biodiversity features.”

Limiting the term terroir to the bedrock and soil therefore does not encapsulate its full meaning. For example, this would mean that the terroir of a vineyard by Lake Bienne cannot simply just be restricted to calcareous soils, while the terroir of a winery in the Leventina district cannot merely be attributed to highly permeable, sandy soils formed from gneiss.

Map of the geology of wine

The map of the geology of wine features twelve types of rock distinguished in a simplified way and divided into two groups – loose rocks that are mostly found near the surface and solid rocks that form part of the bedrock.

However, the nature of simplification means that twelve types of rock can never really reflect the full geological diversity of Switzerland. That is why “assemblages” are introduced as a further category at the end, because the subsurface of wine-growing areas in Switzerland is not always distinguished by one single type of rock, but often by characteristic interbedded strata of different rock types.

Outcrops – where the rock comes to light

A geologist needs “outcrops” to be able to carry out the mapping process. Outcrops are windows that allow geologists to see through the surface layers into the rock below to examine and classify it. In vineyards, outcropping rocks are few and far between as the top soil covers everything. It may, however, be possible to discover an outcrop in a nearby creek, which helps to unravel the mystery of what lies beneath the vineyard. If not, the rock elements of the soil surface or even the composition of the vineyard walls can provide indirect clues as to what makes up the subsoil.