Viticulture
Compared to the annual growth cycle of other Piedmontese grape varieties, Nebbiolo is one of the first varieties to bud and last variety to ripen with harvest taking place in mid to late October. In some vintages, producers are able to pick and complete fermentation of their Barbera and Dolcetto plantings before Nebbiolo is even harvested. To aid in ripening, producers will often plant Nebbiolo in the most favored sites on south and southwestern facing slopes, which give the grape more access to direct sunlight. The most ideal location is at an elevation between 150 and 300 meters (500 and 1,000 ft) and must provide some natural shelter from wind. The vine is very susceptible to coulure, especially if there is wet weather during budbreak or flowering. While rains during this period can affect yield and quantity, rains that occur after the period of veraison can have a detrimental effect on quality. The most highly rated bottles of Piedmont Nebbiolo tend to come from vintages that had dry weather during September & October. Nebbiolo needs sufficient warmth to develop the sugars and fruit flavors needed to balance the grape's naturally high acidity and tannins. In cooler climate areas, such as the subalpine regions of Carema, Valtellina and Donnaz, the grape will produce medium bodied wines with bracing acidity and tannins that need the benefit of a warm vintage.
Nebbiolo does not adapt exceptionally well to various vineyard soil types, preferring soils with high concentration of calcareous marl such as those found on the right bank of the Tanaro river around Alba where Barolo & Barbaresco are produced. The grape can thrive in sandy soils, such as those on the left bank of the Tanaro around the Roero district but the wines from this soil type tend not to be as perfumed - lacking in particular the classic tar aromas. The slightly acidic pH of the sandy Roero soils tend to produce early maturing wines. The lighter wines of Ghemme and Gattinara come from the acidic porphyry soils of the hills between Novara and Vercelli. In the lower Aosta Valley, the soil has a high concentration of granite while the soils of the Valtellina region of Lombardy are predominantly schist based. In addition to soil type, the drainage ability and concentration of magnesium and potassium can have an influencing effect on the type of Nebbiolo wine is produced.
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