GEOPEDOLOGICAL CHARACTERIZATION AND CLIMATIC FRAMEWORK
Geological substrate: SANT’AGATA FOSSIL MARL – TYPICALS; 10 million years old (TORTONIAN STAGE).
Here we find ourselves in the central area of Sant’Agata Marl, within the outcrop of the Marl of Gallo d’Alba. This is the further designation geologists chose in order to identify this area where the Sant’Agata Marl has a well-defined form: bluish strata of constant thickness, with conchoidal fracture, no sandy intercalations, and frequent fossils of organisms at depth. This is the typical form that was the basis for the description of the formation.
Soil: BROWN, MARLY, DEEP, WELL DEVELOPED.
The area where the vineyard is located shows the features that are typical of soils with a certain degree of evolution. When the gradient on a slope is not too marked, the soil can remain a long time and is not continually rejuvenated by the action of water, as in the case of steeper slopes. As a result, the soil tends to become increasingly reddish rather than being white. This indicates to us that the pedogenetic processes (measured in thousands of years) that have a very important effect on the vine have begun. The colour is due to the change in the minerals originally contained in the initial marl, which dissolve releasing manganese and iron oxides. Their metamorphism gives rise to clayey minerals with high exchange capacity, which generate fertility through their action of retaining and releasing nutrients. These newly-formed clays are added to the existing clay in the original marl, resulting in very good fertility. Indeed, the fertility could even be excessive for high quality viticulture, but here the almost total absence of sand means that compaction intervenes to keep everything under control and allow Nebbiolo – an incredibly versatile varietal – to express itself excellently. The colour of the soil on the Castello cru tells us that evolution is present here, but not at the extreme levels of the western side of the great Novello-La Morra ridge.
The further peculiarity that singles out this particular area is the amount of earthy material transported here in ancient times by the Talloria when it used to flow down from much higher altitudes than today. The area can therefore now be considered a fluvial terrace, where the soil is the result of the change in the marl underneath mixed with the earth conveyed by the Talloria from higher up in the Langhe.
This formation represents an exclusive feature within the Barolo growing area.
Climate and topographical framework: SOUTH-WESTERLY aspect; 250 m a.s.l. (820 ft a.s.l.); gradient of c.10%.
The vineyard is positioned on the low hills that frame the Talloria valley. The relatively low altitude and its proximity to the valley expose the area to wide temperature ranges and fairly intense winter frosts. During summer it is marked by a very hot, damp climate. The topographical position of the gently-sloping hillside allows for a good level of water to be maintained, even in the driest periods. This provides the vine with a certain degree of ease in sourcing its water supply, which the tannins in the wine can be traced back to. Moreover, combined with the south-westerly aspect the dark colour of the soil allows it to accumulate heat during the afternoon for release at night, which has as considerable an impact on the aromas as the pebbly soils of Graves in France.
By Edmondo Bonelli, naturalist