Grüner Veltliner

Grüner Veltliner is Austria's defining grape, accounting for roughly a third of the country's vineyard, and it produces a white wine with a flavour almost nothing else has: white pepper.

That peppery note, along with a green, vegetal quality often described as lentil or green bean, is the variety's signature. Around it sit green apple, lime, grapefruit and a wet-stone minerality. Acidity is high, body ranges from light to surprisingly full, and there is frequently a subtle phenolic grip on the finish.

DNA analysis established it as a crossing of Traminer with an obscure variety found as a single surviving vine in St Georgen, Burgenland — a nice piece of detective work, and a reminder of how much European viticulture rests on chance seedlings.

The Wachau, Kremstal and Kamptal along the Danube are the reference regions. Vines grow on steep terraces of primary rock and loess, and the interplay of warm Pannonian air from the east with cold air from the northern forests creates the temperature swing that preserves aromatics. The Wachau's own classification runs Steinfeder, Federspiel and Smaragd in ascending order of ripeness and weight, a system unique to the region.

The lighter styles are made for early drinking and are often sold in litre bottles for exactly that purpose. The Smaragd wines are powerful, dense and capable of twenty years in bottle, developing honey and toast.

It is also unusually good with difficult foods — asparagus, artichoke and green vegetables — which defeat most wines.

The peppery note comes from rotundone, the same compound that gives Syrah its pepper, and it is the clearest chemical link between two grapes that otherwise have nothing in common. It is strongest in cool sites and cool vintages and declines as the fruit ripens, which is part of why the lighter Weinviertel wines are more overtly peppery than the powerful Wachau Smaragds.

The Wachau's own classification is worth knowing since it is unique to the region and appears prominently on labels. Steinfeder is the lightest at up to eleven and a half per cent alcohol, Federspiel the middle tier, and Smaragd the ripest and most concentrated, named for the emerald lizards that sun themselves on the terraces.

It is one of the few wines that genuinely handles asparagus, artichoke and raw green vegetables, foods that make most wine taste metallic. That reliability at the table has done as much for its international reputation as any single bottle.