Geology and Climate
If we were to represent Franciacorta very schematically, we could imagine a large inverted triangle with a vertex in the north that touches the southern shore of Lake Iseo, the eastern side delimited by the mountainous hills of Monticelli Brusati, Ome and Gussago, the western side by the Monte Alto and finally its base outlined by Monte Orfano.
Within this conceptual triangle we can quite crisply and clearly see the shape of the moraine amphitheatre formed during the ice age (in the Secondary and Tertiary geological ages) due to the effect of a large glacier which, coming from Val Camonica, divided into two branches immediately after the basin of the lake, with a small one to the east and one much larger and more important to the west.
The amphitheatre of Lake Iseo, which is substantially of moraine origin, owes its appearance to five main periods in the development of the glacier:
- ithe first period is characterised by the great expansion of the glacier with the formation of the first moraine arc, with the exclusion of the massif of Montorfano, the origin of which is linked to the lifting of the seabed by the tectonic movements of the crust. The remains of this period are constituted by irregular undulations that are not particularly high, such as that of Paderno Franciacorta. Typical lateral moraines, from the oldest to the most recent, can be observed among the reliefs that once tightly closed off the glacial mass;
- The second period was characterised by the glacier remaining in one place, resulting in the formation of a higher and more significant morainic circle. The left side is represented by moraines next to the slopes of Monte Alto, from above Clusane up to Colombaro, and partly by the high hill west of Nigoline. The right side is the most typical and consists of the range of hills that reaches from Fontane to Provezze via Monte Martinello, Monte di Fantecolo and San Giorgio Monterotondo until Bornato. The moraine is a magnificent arc that starts from Adro and develops between Torbiato and Erbusco until Calino. The front and left side of the Iseo amphitheatre consistutes Franciacorta;
- the three subsequent periods were characterised by the glacier’s retreat from the plain of Brescia and the subsequent release of a large amount of moraine material which then, in time, was covered with active soil and gave rise to the rolling hills of Franciacorta.
The moraines are arranged in a series of undulating hills that, given their impressive height, could sometimes be considered mountains.
One of the basic characteristics of Franciacorta’s moraine-originating soils composed in this way (allochthonous soils) is an enormous wealth of added minerals, which are different to those derived only from the rocks found there (autochthonous soils), and this forms the basis for the area’s high-quality viticulture. Vines are perennial shrubs with average life span of at least 30-40 years from planting, but sometimes also live much longer. In order to develop well and express their potential characteristics to fullest, they need a large amount of material that is also rich in micro- and meso-elements that are not absorbed directly in high amounts but are fundamental as catalysts for particular biosynthesis reactions, like those for flavour precursors, for example.
Franciacorta is situated at the extreme northern edge of the Po Valley and is also part of the pre-Alpine system, south of Lake Iseo, therefore, although it is affected by a continental climate, it also derives enormous benefits from the proximity of the lake, which has a huge mitigating effect on temperatures in both summer and winter. Evidence of this lies in Franciacorta’s typically Mediterranean vegetation, which includes both wild or naturalised plant species, and also those that are easy to cultivate, such as the olive tree. Climatologists categorise this area as a Insubrian meso-climatic region.
In summer the typical sultry heat of the Plain is tempered by cool breezes coming across the lake from the Valcamonica. In winter the lake always protects the moraine amphitheatre, from what is now the cold air that comes from Valcamonica. The lake serves as a heat accumulator and the cold air coming from the north is heated a few degrees before coming further south, to Franciacorta.
In summer, the presence of the lake and bog helps establish large masses of moisture. Under these conditions, these masses meet the cold winds coming from the alpine valleys, resulting in frequent storms in spring and summer. In the growing period for the vines (April to October) the average rainfall is 500-600 mm, approximately 2/3 of the annual figure.