Geological quick guide, or does basalt taste good?

What kind of rocks are common in wine-growing regions and more generally, why is this important and how is it related to wine? We spoke to geologist Zsolt Veres, author of the site "akovekmeselnek.hu" (Rocks Tell a Story).

What types of rocks are there and how are they formed?

Rocks are natural systems of minerals that make up the bulk of the Earth’s solid crust. There are three main groups of rocks: igneous, sedimentary and metamorphic. Igneous rocks are formed from magma (e.g. granite) or lava (e.g. rhyolite, andesite, basalt) that is pushed down into the earth’s crust at different depths. The rock-forming grains of sedimentary systems may be deposited in seawater, for example, from minerals derived from other rocks (e.g. sandstone), while limestone and dolomite, for example, may be precipitated by chemical/biological processes in sedimentary waters. The third group is metamorphic rocks (e.g. mica, gneiss), which are formed from the previous two groups of rocks at depths in the Earth’s crust characterised by higher pressures and temperatures.

Cretaceous marl, a rock from the Neszmély Wine District

How does the rock relate to the soil which is deposited on it?

The soils are formed by the uplift of the underlying bedrock and its enrichment with organic matter. The mineral composition, structure, heat and water retention of soils are largely influenced by the bedrock on which they are formed. Just think of the differences between a soil formed on sand in the Kiskunság or a soil formed on basalt in Badacsony.

Why is soil important for vines?

The root of the vines, which penetrate to various depths, take up the water and micro- and macro-nutrients from the soil, with the help and cooperation of the “micro-world” that lives there. The depth, temperature, air and water supply of the soil have a significant influence on the development of the vines living in it. If the soil starts to develop in a way that is unfavourable to the vine, this will also affect its life cycle. Consider a soil that has been saturated in water for a long time, which is not good for the roots and therefore not good for the entire plant.

The lunar-like surface of the basalt of Somló

How does the rock/soil affect the taste of grapes and wine?

The question of whether the bedrock can be reflected in the wine’s flavour has long been an issue for experts. The answer: indirectly, yes! The characteristics of the bedrock and soils on which it is formed influence the character, flavour, acidity and dry extract of the wine that is produced. Under the same climatic conditions, with the same viticultural and oenological technology, the same grape variety produces different wines in different areas. Compare an Olaszrizling from Kunság planted on sand, one from Balatonfüred on limestone or one from Badacsony on basalt!

When you are in a wine region, how do you know what kind of rock is underneath?

The geographical structure of the wine regions is illustrated by various geological maps. In the field, however, you have to look for outcrops of rock in which the rocks that built up the area are found in their original position. If there aren’t any, then the presence of small or large rock fragments in the soil and the excavation of a soil section can provide information about the geological medium.

No, it's not from Mars. Permian red sandstone is also found in the Balatonfüred-Csopak, Pécs and Badacsony Wine Districts.

Zsolt Veres at work