Valtellina is the only specialist Nebbiolo denomination outside of Piemonte in neighbouring Lombardy. Its main town, Sondrio, is 160 kilometres northeast of Milan and 50 kilometres east of Lake Como. The vineyard area is situated on the north side of a broad, glacial valley. The River Adda flows at the bottom of the valley from near the border with Switzerland to the top end of Lake Como. The land rises steeply into the Rhaetian Alps to the north. The wide valley floor is used for apple growing, other crops and the villages; vineyards are to be found only on the slopes. Since at this point, the Adda runs directly from east to west, the valley has created a south-facing steep slope that has been utilised for centuries for vine growing. Because of the steepness of the slope, the patches of vineyard are made possible by an extensive network of dry stone walls. It is estimated that there are 2,500 kilometres of these walls. Maintaining the walls is a major extra burden for growers.
Steep, terraced vineyards in Valtellina
The vineyard area runs for around 50 kilometres, with Sondrio at the centre. As in Alto Piemonte, there used to be many more vineyards on the slopes, but most have been abandoned to the encroaching woods as they are too difficult to work. Today, viticulture here is only for the committed.
In terms of climate, the Alps to the north rise to 3–4,000 m, blocking cold winds and the worst of the weather coming from the north. Warm air from Lake Como helps to raise the temperatures. Summers can be very hot, but with high day/night temperature ranges, the grapes retain acidity. Frost is an issue for the apple trees on the valley floor, but is not generally a problem on the steep slopes. Due to its position close to the mountains, there is constant ventilation and regular rainfall. Given the steepness of the slopes, this is important as installing irrigation would be a mammoth task. Virtually all work has to be done by hand. The soils are made up of sand and schist of granitic origin, making them very poor in terms of fertility and fast draining. Typically, the soil composition is 70 per cent sand, around 20 per cent silt and 10 per cent or less of clay. Soil depth can be as low as 40–120 centimetres. Vines put their roots down deep in fissures in the rock in search of water. In this respect, the conditions closest to Valtellina in Piemonte are found in Bramaterra, which has shallow soils, and Lessona, which has sand.
The principal grape variety here is Chiavennasca, the local name for Nebbiolo. By law, Valtellina Superiore DOCG must be made from a minimum of 90 per cent of Nebbiolo, with up to 10 per cent of other red grape varieties authorised in the region of Lombardy. Many growers still use complementary local rare varieties. The wines must be aged for a minimum of two years before release, one of which must be in wood. There are four designated subzones: Maroggia, Sassella, Grumello, Inferno and Valgella. In addition, there are two other legal categories for DOC(G) wine: Rosso di Valtellina DOC for wines made with the same rules about varieties but with no requirement to age before release, and the traditional rarity, Sforzato or Sfurzat di Valtellina DOCG, which is made with semi-dried grapes.
