Savagnin

Savagnin is the grape behind vin jaune, one of the strangest and most compelling wines in France, and a variety with a family tree that explains a great deal of European viticulture. It is the parent or close relative of an improbable number of grapes — Gewurztraminer is a pink-skinned mutation of it, and it is a parent of Sauvignon Blanc, Chenin Blanc, Silvaner and Grüner Veltliner among others.

In the Jura, the narrow strip of hills between Burgundy and Switzerland, it is grown on grey and blue marl soils and made in two opposing ways. Ouillé means topped up: the barrel is regularly refilled to exclude air, and the wine that results is taut, citrus-driven and mineral, recognisably a conventional white.

The other way is to do nothing. The barrel is left deliberately unfilled for a minimum of six years and three months, and a film of yeast called the voile forms on the surface — the same biological process that produces fino sherry, arrived at independently. The wine underneath oxidises slowly and develops a profile with no real equivalent: walnut, green apple, curry spice, bruised pear, dried ginger, and a piercing, salty, almost searing finish.

The finished vin jaune is bottled in a clavelin, a squat 62cl bottle whose capacity is said to represent what remains of a litre after six years of evaporation. It is extraordinarily long-lived; bottles from the nineteenth century are still drinkable.

In the Swiss Valais the same grape is called Heida or Païen and makes dry alpine whites at high altitude, with none of the oxidative character and a good deal of nervy precision.