THE GEO-VITICULTURAL MAP OF THE VALLE DEGLI ASILI WITH MGA's (aka CRU's)

The map shown below is based on the beautiful map published by ENOGEA (curated by Alessandro Masnaghetti Editore) covering the entire Barbaresco region. This map (and others published by the same editor) is essential for understanding the Barbaresco territory. It is also worth noting that Alessandro Masnaghetti was a pioneer in creating these maps—starting with the MGA of Barbaresco—and has spent years refining both the maps and their web-based services. Anyone with an interest in wines (including French wines) should have access to these maps and their accompanying explanatory books, without which it is nearly impossible to fully grasp the reality of the region. 

The meticulousness and precision with which these maps are created cannot be fully appreciated until one actually speaks with Alessandro Masnaghetti: only then does one truly understand the immense cultural and educational value of his work.

La nostra mappe è ovviamente limitata alla sola regione della Valle degli Asili (e dunque manca di una visione più ampia del Territorio di Barbaresco che si può avere acquistando la mappa originale) ma è di per sè già molto interessante.

The original map has been completely revised in terms of colors and graphics, but the geological and technical data, as shown in the two subsequent images, remain unchanged.

A glance at the maps immediately reveals that the area where Tenuta Ca’ Grossa is situated is composed of well-developed soils, unlike the western part of the valley, which is made up of younger soils. The difference between these two soil types is far from negligible; first, it is important to clarify exactly what is meant by the term “soil.”

"The term soil refers to the surface layer of the terrain into which the vines sink a large part of their roots, while sub-soil indicates the stratum just below.The soil, which is generated by the chemical-physical alterations of the underlaying stratum and by the actionsof the organic substances, has been subsequently dividet into young soils and evolved soils, because they differsignificantly from the viticultural point of view. (Mesnaghetti).

1. Young soils, that are created by the continous eorsive action of atmospheric agents mantain the the chaacteristic of the formation (in this case Sant'Agata Fossile Marls) from which they were generated.
2. Evolved soils typical of hillsides of lesser steepness and therefore less suject to erosion, and created by more vigorous chemical-physical alteration of which their more intense coloration is only the most evident sign.

The distinction between young and evolved soils is not just academic—it reflects a real and significant difference in soil characteristics. This is especially important for Nebbiolo grown for Barbaresco, a grape variety highly sensitive to the soil it grows in, as it directly influences the final taste of the wine. Young soils are generally low in nutrients and hold water poorly. While this can be advantageous in wet years, it becomes a drawback in dry ones, such as the extremely hot summers of 2022 and 2023.

In contrast, evoluted soils form through a more extensive breakdown of the less stable mineral components—those that detach more easily from the subsoil—of the parent rock. Unlike young soils, which rely directly on the subsoil for nutrients and often face limitations in nutrient availability, evolved soils generate new clay minerals while simultaneously releasing natural nutrients (not from fertilizers) and iron oxides. It is these iron oxides that give the soils their characteristic reddish-brown hue.

An important consequence of this, especially in a period of global warming and increasingly hot summers, is that these soils are water-efficient. They (evolved soils) retain rainwater far better than young soils, allowing vine roots to access deep water reserves during hot or extremely hot summers. This keeps the leaves greener, promoting better chlorophyll synthesis.

Another important difference is the pH balance of evolved soils compared to young soils, which typically have a pH above 8. This brings another advantage: evoluted soils are characterized by greater nutrient mobility and slower mineralization of organic matter (meaning that organic material takes longer to dry out and lose nutrients, reducing the need for fertilization), resulting in higher fertility compared to young soils.

Finally, it should be noted that the content of fine materials, such as clays and fine silt, relative to sand, allows for greater water retention. While the Valle degli Asili area has a sand content between 15% and 22%, other areas of Barbaresco have a significantly higher sand content: in the Treiso area, between 29% and 35% (with average fertility in young soils), and in the area towards Neive, between 25% and 32% (also with average fertility in young soils).

All of this discussion serves to explain that the purchase of a wine cannot and should not be based solely on the name of a producer: many factors determine the final taste of the wine. Therefore, buying Barbaresco wine from the western part of Valle degli Asili for the 2022 and 2023 vintages (very dry years) carries the risk of obtaining a wine made from vines stressed by drought, which generally require more care due to the lower fertility of the soil. Extending this reasoning to the entire Barbaresco territory, a wine produced in Treiso will differ significantly from one produced in Valle degli Asili, which, thanks to its climatic conditions, optimal altitude, and specific geological characteristics, represents the highest expression of the Barbaresco terroir.