Vin jaune

Vin jaune is a special and characteristic type of white wine made in the Jura region in eastern France. It is similar to dry fino Sherry and gets its character from being matured in a barrel under a film of yeast, known as the voile, on the wine's surface. Vin jaune shares many similarities with Sherry, including some aromas, but unlike Sherry, it is not a fortified wine. The wine is made from the Savagnin grape, with some of the most premium examples coming from the marl based vineyards in the Château-Chalon AOC. In other French wine regions, there has been experimentation in producing similar style wines from Chardonnay and other local grape varieties using cultured yeast such as the vin de voile wine produced in the Gaillac. Vin jaune is made from late harvest Savagnin grapes, a white variety in the Traminer family which is less aromatic than the better-known Gewürztraminer. The grapes are usually harvested in late October when the sugars have developed enough to have a potential alcohol level of 13–15% for the finished wine. The grapes are fermented slowly and then kept in small old oak casks that hold 228 liters (60 gallons). The casks are not topped up, as they are with most wines, so evaporation creates an air gap above the wine. A film of yeast grows over the wine, protecting it partially (but not totally) from oxidation. In Jura, this film is called the voile (veil), but it is similar to the more familiar "flor" in Sherry production. The voile yeast has many similar properties to "flor" but thrives better in a lower alcohol environment and develops less heavily and thickly than "flor" does. The voile typically takes two to three years to develop fully. During this time the wine is exposed to slight levels of oxidation that provoke chemical changes that produce acetaldehyde (as well as ethanol, standard alcohol) and the aroma compound of sotolon. These compounds contribute to the unique flavors and aromas associated with vin jaune. Winemakers must carefully observe the wine throughout the aging process as there is a risk of it developing the wine fault of volatile acidity.

Source: Wikipedia