The Nebbiolo is one of the most demanding and slowest growing grape varieties. Only on steep slopes facing south and south-west and on calcareous marl soil can it develop its qualities and mature into a heavy and deep wine with an alcohol content of up to 15% vol. 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 on the basis of Nebbiolo include Barolo, Barbaresco, Roero, Nebbiolo d´Alba, Langhe Nebbiolo and Sforzato di Valtellina. Its high tannin and acid content as well as its aroma, which is reminiscent of rose, mint, tobacco, cherry, strawberry and raspberry, are also characteristic. 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. Den Vilasar is made there from the berries of Nebbiolo. The classic growing areas are mainly Piedmont and, of much less importance, Lombardy and the Aosta Valley. It is believed that the wine was already grown in ancient times on the hill areas of Monteferrato and Langhe.
The name of the grape variety is a derivative of Nebel (Italian: nebbia), for which there are two theories. According to the first theory, this is due to the fact that it depends on fog to develop its quality. According to the second theory, the name was given due to the white coating that forms on the surface of the thick-skinned and small-berry variety when fully ripe. Due to its dependence on fog, strong fluctuations from year to year are a problem. Other problems with ripening concern susceptibility to powdery mildew, gray mold rot and trickling in damp weather.
Secondary fermentation can be desirable or undesirable for a wine. Unwanted secondary fermentation results in wine defects. These come about when not all of the yeast cells in the wine have been removed, so that the not yet fully fermented sugar residues react and ferment again 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 thus spoiled.
Malolactic fermentation can also be undesirable if the wine has not yet fully fermented, resulting in undesirable malolactic fermentation. 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 rotten yoghurt. Due to the rapid increase in bacteria, the wine becomes cloudy and develops unpleasant sour fermentation aromas.
Malolactic fermentation can also be used in a controlled and dosed manner in order to give the wine a milder and rounder taste, as the Lactic acid tastes not nearly as sour 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.