The effect of soil on wine

It is easy to think that it’s soil that gives the aroma to the wine. After all, if you look at the Bourgogne and Alsace regions, the different tastes of Pinot Noir lust come from something and this something must be the difference in the soil.

If this idea is interesting, it is also mostly wrong. If you look at the Bourgogne crues, many of them have different soil types, limestone and clay on one side, granite and Silex on the other. Does it mean that soil does not play a role in the wine’s aroma and texture? No, but not the one you can imagine.

Vine is a photosynthesis plant. It produces its energy by using sunlight and CO2 in the atmosphere. This produces sugar. But grape vines also need some elements from the soil. The most important is water. Water is collected in the soil by the root system of the plant. The soil is the main water source for the plant.

Grape Vine, like other plants, need also some other nutrients. The most important is Nitrogen, which is needed for protein production. Plants also need minerals like calcium, phosphorus, potassium, sulfur, magnesium, silicon, and other micronutrients (zinc, iron, copper, …). These minerals come in ionic form, dissolved in the water, and absorbed by the root in the soil. Unlike other plants, vines don’t need much mineral to prosper. However, any deficiency could impact the wine quality.

The soil is the main source of water and nutrients for the Vine. But what do we know about the soil? Soil is a complex system. To simplify we can divide the soil into 3 layers. The surface layer is where organic compounds are found, decomposing plant debris, bacteria, and fungi. The second layer is composed of the degradation of rock, and the last layer is the parent work of the sol. The formation of the soil is the result of the degradation of organic matter and mineral matter.

The terroir effect of the soil is the ability to manage water supply. Soil can retain water, but the amount of retained water is different depending on the texture of the soil. The vine needs water but also needs restriction called hydric stress, to give concentrated grapes. The level of water a soil can retain is crucial for fine wine. If the soil contains a lot of water, the wine will be less concentrated and with less aroma, and with too much water deprivation, the grape fails to maturate.

The texture of the soil, more than its composition, is the factor of wine quality. A soil composed of fine particles will retain more water than a soil composed of rocks. But soil is not composed of only one element, it’s a mix of sand, rocks, clay, limestone, and silt. , but there is often a more dominant material.

The soil texture and the dominant material can help to predict the style of the wine. With sand, wine is often bold, clay is associated with light wine for example.

We can even make a short list of soil rock and the wine profile:

• Shale soil: Bold and powerful wine
• Granite: fine wine
• Chalk: fresh and fruity wine
• Volcanic soil: fruity wine
• marl: fine and powerful wine
• limestone: balanced fine wine
• clay-limestone: fruity and balanced wine
• sandstone: fresh wine
• grave: powerful and bold wine

These are some examples of wine types associated with the dominant material in the soil. Of course, many other factors could influence the wine taste, local climate, variety, winemaking, and farming methods. But it can give you an idea of what to expect when you get wine from chalk or volcanic soil.