The rosé has gone back in the rack, the evenings have that first proper bite to them, and the wine you want is no longer the one you wanted in July. Autumn asks for red, but not yet the big, brooding sort that belongs to December. What it asks for is Gredos Garnacha: a mountain wine from the granite hills west of Madrid that has quietly become the most talked-about red in Spain, and the one sommeliers keep comparing, a little breathlessly, to Burgundy.

Garnacha has spent most of its life being underestimated. For decades it was the workhorse of hot, dry Spain and the southern Rhône, the grape that turned sunshine into something big, sweet and a touch clumsy. Then a handful of growers went up a mountain, and everything changed.

The mountain is the Sierra de Gredos, and the wines coming off it look nothing like the Garnacha of old. They are pale, perfumed and almost weightless, built on freshness rather than force. If you have written the grape off, this is the range that rewrites it.

A mountain nobody was watching

Gredos is the spine of granite that runs west of Madrid, straddling Ávila, Toledo and the capital's own hills. Vines here sit high, some of them well above 900 metres, on thin sandy soils broken from the rock. The old Garnacha bush vines, gnarled and low-yielding, were for years considered barely worth farming, and growers were pulling them out. A few people looked at the same vines and saw the opposite: fruit grown slowly in cool mountain air, holding on to its acidity and its scent in a way the lowland vineyards never could.

Just south, in the old Garnacha heartland of Méntrida, the story is the same. Altitude does to Garnacha what it does to any grape: it stretches the growing season, keeps the nights cold, and lets the fruit ripen without cooking. The result is a red with the perfume of the hills and none of the heaviness you might brace for.

Why Gredos Garnacha drinks the way it does

Pour a glass and the first surprise is the colour: translucent, closer to a ruby than the inky purple Garnacha is supposed to be. Then the smell, which is where these wines really make their case. Wild strawberry and raspberry, dried thyme and rosemary off the hillside, a little woodsmoke, a twist of orange peel. It is red fruit with its shoes off, loose and aromatic and alive.

On the palate they are light on their feet, with fine, powdery tannin and a savoury, mineral edge that comes straight from the granite. This is the comparison critics keep reaching for: village Burgundy, cool-climate Pinot Noir, the kind of red that refreshes rather than fills. It is also exactly what autumn wants. Warm enough for the turning weather, light enough that you can still see the table through the glass.

The names to know

The project that lit the fuse is Comando G, the work of Fernando García and Dani Landi, two growers who went hunting for old, high vines and made wines so precise they turned Gredos into a pilgrimage. Their La Bruja de Rozas is the accessible one, a whole village's worth of charm in a bottle. Landi's own Vitícole Mentridana wines make the Méntrida case just as well; El Mentridano is a lovely, savoury introduction to it.

Then there is Pepe Rodríguez de Vera, whose Atalaque wines are, to our minds, some of the smartest buys in Spain right now. The everyday Las Cárcavas Garnacha over-delivers wildly for the money; the single-parcel Garnacha del Horcajo, from old bush vines, is the one to sit with when you want to see how far the style can go. And at the very top of the tree sits Álvaro Palacios, the man who rebuilt Priorat, now making a single-vineyard Garnacha called Quiñón de Valmira in Rioja that ranks among the most coveted reds in the country.

Where to start

You do not need to spend a fortune to understand what the fuss is about. Start with something under fifteen pounds and drink it on a weeknight; the whole point of this style is that it wears its pedigree lightly. Then, when you want to give it your full attention, trade up to a single-vineyard bottling and give it a decent glass and half an hour of air. The two below are the ladder in miniature: the everyday, and the one to sit with, both from the same grower's hands in Méntrida.

How to drink it this autumn

Serve these wines cool. Not fridge-cold, but twenty minutes in the fridge door will do them a favour, lifting the perfume and sharpening the freshness. This is one red that genuinely benefits from a light chill. At the table they are a gift to autumn cooking: roast chicken and its skin, a plate of mushrooms on toast, lentils and sausage, anything with a bit of earth and char. They will handle the first game of the season without flinching, and they will not flatten a simple Tuesday supper either.

If you want the grape's full story, our guide to Grenache and Garnacha covers the ground from the Rhône to Australia. For the wider country, start with our Spanish wine regions guide, and for Gredos's more powerful cousins, read up on Priorat and Rioja.

Gredos has stopped being a secret. The sommeliers know, the collectors know, and the prices at the top end are starting to reflect it. But the beauty of this corner of Spain is that the magic is not reserved for the grail bottles. Even the everyday wines carry the mountain in them: that cool, wild, perfumed lift that no amount of sunshine can fake. The label just says Garnacha. The glass says something rather more interesting.