Nebbiolo

Nebbiolo is Italy's most demanding great grape and the variety behind Barolo and Barbaresco. Its name is usually connected to nebbia, fog — either the autumn mist that settles in the Langhe valleys as it ripens, or the pale bloom on the ripe berries.

It is a study in contradiction. The wine is pale, often garnet and translucent even when young, and can look like a much lighter red than it is. What follows is anything but light: ferocious tannin, very high acidity and a powerful aromatic presence of rose petal, tar, sour cherry, dried herbs, liquorice and, with age, truffle, leather and dried roses.

That combination of pale colour with formidable structure is unusual, and it is why Nebbiolo needs time. Traditional Barolo was macerated for weeks and aged in large old Slavonian oak for years; the modernist approach of the 1980s and 1990s used shorter maceration and French barriques to produce more approachable wine, and the dispute between the two camps was fierce enough to be called the Barolo wars. Most producers now sit somewhere between.

It is extraordinarily site-sensitive, and the Langhe's crus — Cannubi, Brunate, Monfortino's Francia, Barbaresco's Asili and Rabajà — produce recognisably different wines from the same clone.

It ripens very late, after every other Piedmontese variety, and takes the best south-facing slopes as a matter of course.

In northern Piedmont and Valtellina it is Spanna and Chiavennasca, making lighter, higher-altitude versions.

The tannin is worth understanding, because it determines how the wine should be handled. Nebbiolo's tannins are unusually fine-grained but present in enormous quantity, which is why a young Barolo can feel simultaneously delicate and punishing. They soften slowly rather than dropping out, and a wine that is astringent at five years is often glorious at twenty.

The colour behaves oddly too. Nebbiolo has relatively little anthocyanin and what it has is unstable, so the wine starts pale garnet and browns at the rim within a few years — a visual cue that would indicate old age in a Cabernet and means very little here.

It is famously reluctant to travel. Attempts to grow it in California, Australia and Argentina have produced competent wine and almost nothing with the aromatic complexity of the Langhe, and the general conclusion is that it needs the specific combination of calcareous marl, autumn fog and a very long hang time that Piedmont provides.