Term (Spanish rancio = rancid) for wines from hot wine-growing regions that have undergone oxidative ageing with simultaneous exposure to heat. However, the temperature is lower than in the related process of madeirisation, so that in rancio the notes of nuts and rancid butter tend to predominate, whereas in Madeira a caramel note dominates. In common parlance, rancio is also used for the typical wine taste of candied fruit, nuts and rancid butter. Ranciotone is produced by oxidation of fatty acids and formation of butyric acids. Other Rancio-style wines are Banyuls, Fondillón, Maury, Rasteau and Rivesaltes. Cognacs aged for a very long time in the barrel also take on a Rancio tone (Rancio charentais). In French Vin Jaune and Italian Vin Santo, the term rancio is sometimes used incorrectly. Related terms are firnig, madeirised, oxidised, rahn and rancio.
In the Spanish region of Catalonia, rancio is a speciality produced in numerous varieties from dry to sweet. Here, predominantly white wines are made oxidative by selective exposure to oxygen through only loosely closed fermenter openings. The wine is fortified to 18 to 19% alcohol by volume and then aged in oak barrels or pear-shaped bombonas (glass balloons), the containers often deliberately exposed to heat or extreme temperature fluctuations in warehouses that are hot during the day and cool at night. The high alcohol content prevents the development of acetobacter (acetic acid bacteria). After several years of ageing, a rancio is blended with mistela (fortified must) or arrope (grape juice concentrate) to achieve the desired sweetness level.
