Nebbiolo is one of the most demanding and slowest-growing grape varieties. It can only develop its qualities and mature into a heavy and profound wine with an alcohol content of up to 15% vol. on steep slopes facing south and south-west and on calcareous marl soil. The grape variety offers the world record of being the basis for most DOCG wines despite the small area under cultivation. The DOCG wines made from Nebbiolo include Barolo, Barbaresco, Roero, Nebbiolo d'Alba, Langhe Nebbiolo and Sforzato di Valtellina. It is also characterized by its high tannin and acid content and its aroma reminiscent of rose, mint, tobacco, cherry, strawberry and raspberry. The bouquet offers the basic tone of rose and violet with hints of truffle, tar, tobacco and dark chocolate.
All attempts to grow the wine overseas have so far been doomed to failure. The only exception are slopes in Uruguay, which meet the strict conditions of the grape variety. There, Den Vilasar is made from the berries of Nebbiolo. The classic growing areas are above all Piedmont and, to a much lesser extent, Lombardy and the Aosta Valley. It is believed that the wine was already being cultivated in ancient times on the hilly areas of the Monteferrato and the Langhe.
The name of the grape variety is derived from fog (Italian: nebbia), for which there are two theories. According to the first theory, this is because it depends on fog to develop its quality. According to the second theory, the name came from the white coating that forms on the surface of the thick-skinned and small-berry variety when it is fully ripe. Due to its dependence on fog, strong vintage-to-vintage variations are a problem. Other ripening problems include susceptibility to powdery mildew, gray mold and trickling in damp weather.
Secondary fermentation can be desirable or undesirable for a wine. Undesirable secondary fermentation causes wine defects. These occur when not all yeast cells in the wine have been removed, so that the sugar residues that have not yet fully fermented react and ferment through contact with the yeast cells. This process is further promoted by excessive heat during storage and a lack of sulphurisation. The wine becomes cloudy, develops carbon dioxide, overpressure is possible and the wine tastes musty, fermented and unattractive. It is therefore spoiled.
Malolactic fermentation can also be undesirable if the wine is not yet fully fermented, resulting in undesirable biological acid degradation. During this fermentation, the lactic acid bacteria convert the malic acid into lactic acid. If the wine tips over, it tastes like burnt milk and spoiled yoghurt. Due to the rapid multiplication of bacteria, the wine also becomes cloudy here and develops unpleasant sour fermentation aromas.
Malolactic fermentation can also be used in a controlled and dosed manner to give the wine a milder and rounder taste, since the Lactic acid does not taste nearly as acidic as malic acid. Secondary fermentation is also desired when sugar and yeast are added to champagne and sparkling wine in a controlled manner. The fermentation carbonic acid cannot escape, the drink receives an overpressure of around 6 bar and thus its refreshing pearly taste.