Vin Jaune flies in the face of viticultural orthodoxy.
It is a rebel, a wine that somehow miraculously weathers the slings and arrows of time to gain a depth and complexity that makes it unlike any other wine on Earth. Though the most obvious comparison is with Spain's oxidized Sherry, Vin Jaune is denser and more robust, and it also has a strong tail of acidity that Sherry simply does not.
Made from the pugnacious Savagnin grape, Vin Jaune is fermented like any other wine. But that's just the beginning. After the fermentation, the wine is stored in large barrels that are never completely filled and are basically abandoned (meaning they certainly aren't topped off) as the wine goes through a period of existentialist soul-searching for a minimum of six years and three months. It's lonely being a Vin Jaune.
As you can imagine, a tremendous amount of the wine evaporates over this time (angels drink well in the Jura). Here, legend has it that the squat 620 ml bottles - called clavelins - are all that remain of a liter of wine after its journey.
At the beginning of the aging process, a thin veil of yeast cells forms, protecting the wine from severe oxidation. In contrast to nearly all other wines, temperature fluctuation is important to Vin Jaune. Barrels are often stored in attics, and radical temperature fluctuations frequently occur, often exceeding 22 degree differentials.
Suffice it to say that making Vin Jaune is risky business. If everything goes perfectly, you're destined to lose about a third of your product! If anything goes haywire, entire barrels can be lost - and this happens a lot (chaos is, well, chaotic). The rejection rate of Vin Jaune varies from producer to producer and vintage to vintage, but it can be as high as 75%.
The major enemy of a successful barrel of Vin Juane is volatile acidity. The bacterias that form acetic acid (the major component in volatile acidity and vinegar) thrive in Vin Jaune's oxygen-rich environment. As such, frequent laboratory analysis of Vin Jaune must occur to monitor acetic acid levels. That said, if a barrel of Vin Jaune emerges alive from its journey, it's nearly indestructible: Bottles are capable of aging for well over 100 years.