What is Sémillon and where does it come from?

It's a thin-skinned white grape from Bordeaux, in south-west France, and it's been there for centuries. Two claims to fame: it's the backbone of the sweet wines of Sauternes and Barsac, and the age-worthy dry partner to Sauvignon Blanc in Pessac-Léognan and Graves. Low in acid, rich in texture — and that thin skin is the whole point, because it welcomes noble rot, the benign fungus that makes great sweet wine possible.

Is Sémillon a sweet or a dry wine?

Both, and that's the fun of it. In Sauternes, Barsac and the sweet appellations around them, botrytis-affected Sémillon makes some of the world's most celebrated dessert wines — honeyed, unctuous, built to last decades. Blend it with Sauvignon Blanc, ferment and age it in barrel in Pessac-Léognan and Graves, and the same grape gives you serious, long-lived dry whites. The grape brings richness either way. The vineyard and the cellar decide sweet or dry.

What does Sémillon taste like?

Young and dry, it's citrus, pear, fresh fig and a distinctive waxy, lanolin note, often with a lick of oak. Give it years and it turns toasty, honeyed and nutty, with a beeswax richness that starts to read like fine white Burgundy. In its sweet, botrytised form it's another wine entirely: apricot, honey, marmalade, saffron, candied citrus — all of it held up by a thread of fresh acidity, so it rarely cloys.

Where should I go to taste Sémillon in France?

Bordeaux, no contest. For the sweet side, drive south to the châteaux of Sauternes and Barsac, about forty minutes out of the city. For the dry, ageworthy style, Pessac-Léognan and Graves — some of it right in Bordeaux's own suburbs, so you barely need a car. Most estates see visitors by appointment, so book ahead, and book well ahead if you're coming for the autumn harvest.

Sémillon

Chardonnay gets the fame. Sauvignon Blanc gets the noise. Sémillon gets the cellar.

This is the quiet one — the golden, thin-skinned white at the heart of Bordeaux that rarely puts its name on the label and almost never gets top billing. And yet, when people argue about the greatest white wine France makes, they're usually arguing about Sémillon without saying so. From one grape, south-west France pulls off two completely different masterpieces: the honeyed, decades-lived sweet wines of Sauternes and Barsac, and the taut, age-worthy dry whites of Pessac-Léognan and Graves. Learn to spot it and you've unlocked half of white Bordeaux.

The one trick that explains everything

Everything about Sémillon comes back to its skin. It's thin — thinner than almost any other great white grape — and that's not a weakness here, it's the whole gift. That thin skin is why the noble rot gets in.

The grape itself is low in acid and rich in texture, with a waxy, lanolin thread running through it: fresh fig, pear, citrus, a faint note of beeswax when young, turning toasty and nutty with age. On its own that makes a good wine. But when Botrytis cinerea — the "noble rot" — shrivels those thin-skinned berries on the vine and concentrates everything inside them, it makes an immortal one. No other grape says yes to botrytis quite so readily. That single quirk of biology is why Sémillon, more than anything else in the vineyard, is the raw material of the world's great sweet wines.

Its home is the gravel and limestone country south of Bordeaux, and it's been there for centuries. A hundred years ago it was one of the most-planted white grapes on earth. Fashion has since chased crisper, louder whites and its acreage has shrunk — but what's left is concentrated exactly where it counts.

Where it turns rot into gold

Nowhere else on earth turns a grape's vulnerability into greatness the way Sauternes turns rot into gold.

Start here, because this is the summit. In Sauternes and Barsac, a short drive south of the city, a small cool river called the Ciron slips into the warmer Garonne and throws up autumn mists that pool over the vineyards at dawn and burn off by afternoon. That damp-then-dry rhythm, day after day, is precisely what noble rot needs. The fungus shrivels the grapes, pickers go through the rows again and again taking only the affected bunches, and the yields end up famously, almost absurdly, tiny. The labour is enormous. The wine is worth it.

What you get is apricot, honey, marmalade, saffron and candied citrus, strung on a line of fresh acidity that keeps it from ever going flat or sticky — and it can age for decades. Sémillon supplies the body and the honeyed core and the botrytis affinity; Sauvignon Blanc adds lift; a little Muscadelle sometimes rounds it out. At the top sits Château d'Yquem, the sole Premier Cru Supérieur of the 1855 classification, with Climens and Coutet flying the flag in Barsac and Suduiraut and Guiraud in Sauternes. France has other sweet traditions — Monbazillac over in the Dordogne, the botrytis Chenin of the Loire — but the Bordeaux originals are Sémillon's, and no one has ever bettered them.

The dry side almost nobody expects

Here's the part that surprises people at the table: Sémillon makes bone-dry white, and it's serious. In Pessac-Léognan and the wider Graves — some of it inside Bordeaux's own suburbs — it's blended with Sauvignon Blanc, fermented and aged in oak, and turned into dry whites with real weight and a long life. Young, they give you citrus, fig and a creamy, waxy pull. Leave the best a decade and they go honeyed, toasty and complex — close to a fine white Burgundy in register, but with their own signature.

These are among the longest-lived dry whites in the country. Château Haut-Brion Blanc, Domaine de Chevalier and Smith Haut Lafitte make the case at the summit; a deep field of Graves estates makes it for a lot less. And out in the sprawling Entre-Deux-Mers, the same Sémillon-Sauvignon partnership turns out light, fresh, drink-tonight whites — the everyday face of Bordeaux Blanc.

Style	Where	How it tastes
Great sweet	Sauternes, Barsac	Apricot, honey, marmalade, saffron; unctuous, decades-lived
Serious dry	Pessac-Léognan, Graves	Citrus, fig, wax young; toasty and honeyed with age
Everyday dry	Entre-Deux-Mers, Bordeaux Blanc	Fresh, light, citrus-and-pear; drink young

Two day trips, two Sémillons

Meet both, and give each its own day. The two styles want different roads out of the city.

For the sweet wines, point south. Sauternes and Barsac sit about forty minutes below Bordeaux through the pine-and-vine country of the southern Graves. The move to make once you're inside a château: taste a young vintage against an older one, back to back. Nothing teaches you what botrytis and time do to a wine faster. Come in autumn, during and just after the staggered harvest, and the whole place is alive — mist on the vines, pickers everywhere — but it's also the busiest stretch of the year, so book well ahead.

For the dry whites, don't even leave town. Pessac-Léognan starts in Bordeaux's southern suburbs, which makes it about the easiest fine-wine appellation in France to visit without a car — the one to slot in when you've only got a spare afternoon. Ask for the cellar tour that ends in a side-by-side of the estate's white and red; several do it, and it's the clearest way to see how much these whites carry. Either trip, plan in advance — Bordeaux's serious estates run on appointments, not drop-ins — and use the France hub to line the region up with the rest of a French wine run.

At the table

Sweet Sémillon is one of the great food wines, and dessert is the least of it. The classic Bordeaux move is Roquefort, salt meeting honey across the glass — do this one at least once. It's just as happy with foie gras, with rich poultry, and, the trick worth stealing, with spicy Asian food, where the sweetness cools the heat. Fruit tarts and crème brûlée, sure. Just don't cage it there.

Dry Sémillon, low in acid and waxy in weight, wants richer plates than a zippy Sauvignon would. Roast chicken and pork, creamy fish and shellfish, veal, soft and washed-rind cheeses. The barrel-aged Pessac-Léognan style, in particular, stands up to anything you'd pour a white Burgundy for.

Sémillon travels — it does remarkable things in Australia's Hunter Valley and beyond — but France is where it was born and where it still does its best, and most, work. Follow it to the source and you'll understand white Bordeaux from the inside.