First there was the sea. Dry and wet alternating seasons. The erosion of the surrounding alpine arc brought into the sea layers and layers of sand and silt. From here we have a unique soil composition, like unique is the composition of the alps that surrounds us.
The calm ends: the alps rise
In three eras the Langhe emerged Serravallian, Tortonian, and Messinian. Respectively 12, 9 and 5 millions years ago.
Serravallian, gives origins to what is known as Lequio formations, found in the Southern area of Barbaresco (South of Neive and Treiso), and in South-East Barolo (South of Serralunga and East of Monforte d’Alba).
This soils are pourer, with percentage of limestone, clay, loam and sand moderately variable from hill to hill.
These soils normally have high percentage of limestone, and could present more gross texture, and high percentage of sand. This is due to the basin that at that time was very deep, was then characterized from landslides and strong water flows that caused this stratification. They can be easily identified because of the steepness of their slopes; these high valleys give a higher erodibility.
The soils that originate from Tortonian can be distinguished in two categories:
- Diano Sandstones: missing in Barbaresco, these characterize north of Castiglione Falletto, the central part of Monforte d’Alba and in small part Barolo too. There is also a long descent of these soils from the village of Diano d’Alba towards Alba. Composed by big sandstones.
- Sant’Agata marl: the most common soils of the lower part of the Langhe. Those are presents in most of Barbaresco (Barbaresco, South of Neive and Treiso) and a great portion of Barolo (Most of Barolo, East of La Morra, Novello, West and North-East of Moforte d’Alba, North of Serralunga d’Alba and Grinzane Cavour. Easily identified by the greyish-blue color of those.
Those can be also divided in:
- Marne di Sant’Agata sabbiose: transition point, there is more homogeneity between these marls’ layers, but still high percentage of sand can still be found, due to large submarine slides, characterized by a finer texture. We observe them in Western Neive, North of Treiso, and South of Barbaresco. In Barolo they are very common in Castiglione Falletto and around the village of Barolo and East and West of Monforte d’Alba. Hills quite steep and quite high.
- Marne di Sant’Agata tipiche: Fine texture e regular layers, due to the calmer sea bottom. Probably found in the neighbourhood of the village of Barbaresco, but in Barolo they are found in South of Serralunga d’Alba, Grinza Cavour, the eastern part of La Morra, and the lower parts of the hills in Castiglione Falletto.
- Marne di Sant’Agata laminate: very thin layers, accumulated when the sea started to be very calm, gives origin to very gentle hills. It can be found in a long stripe, starting with Verduno, going South towards East of La Morra village, and Western Barolo, ending in Novello.
Messinian is the more recent period, they are characterized by less limestone concentration and chalk, especially in what in the chalk vein. Absent from Barbaresco can be found on the western part of La Morra and Verduno.
Superficial soils have evolved along time, exposures and different cultivations, have increased soil heterogeneity, even if the subsoil is the same, top soil can highly differ. Slope plays a major role in washouts, the steeper the higher the similarity between top and subsoil. Moreover, retention of water is less in steep hills. The steepest hills tend to balance elegance and power in better terms, and as a consequence tend to be preferred for great expressions of Nebbiolo.
On average Barbaresco can be defined as Silty-Loam, Nebbiolo in these soils exhibit his extreme finesse and elegance. While Barolo with a Clay-Loam average soil, tends to show more opulence.