Savagnin spends six years and three months in old barrels that are never topped up; in the emptying headspace a veil of yeast forms over the wine and slowly transmutes it — France's cousin to fino sherry, arrived at independently in the Jura. It is bottled in the 62 cl clavelin, said to be what remains of a litre after the angels have taken their share.
The result is dry, golden and piercing: walnut, curry spice and green apple over an acidity that lets bottles open decades later. Château- Chalon is its citadel appellation, and each February the Percée du Vin Jaune festival broaches the new vintage. Louis Pasteur, a Jura native, kept a vineyard at Arbois and studied fermentation on his own vines — the science of wine begun beside its strangest example.