This is probably one of the more interesting things about Jura. They make their own distinctive kind of wine called vin jaune (yellow wine), which comes from the Savagnin grape. After the wine has been fermented it's placed into the barrels, but the barrels are never topped off, so a thin film of yeasts forms. In February they even have a festival where they pierce the film (I called it sludge) after 5 years and three months since the wine was first placed in the barrels.
The wine is pretty distinctive, and it's one of those things that you have to try more than a couple of times before you can say you like it or not. Because of the different way that the wine is made, the wine also lasts practically forever. One guy we were talking to says that his family has wine that is 70 years old, and they are thinking about maybe drinking a bottle.