September is probably the strangest month in the wine-drinking calendar. With a nip in the evenings, summer's crisp, fresh white whites are beginning to seem as out of place as crisp, white cottons. Yet it's a bit too soon to get wrapped up in the red wines we'll need to see us through autumn, winter and - given Irish weather - a fat slice of spring. Here's an unusual answer: Semillon. A white wine with body and flavour - a half-way house for the lighter meats that will bridge the gap between summery salads and full-blooded winter beef.
It's an oddball, really - one of the great, unsung heroes of the wine world which has only itself to blame for its shadowy profile, because it's hard to find and even harder to understand. It's far more common to see Semillon credited on labels alongside some other grape than standing alone. Pleasant as blends like Semillon-Chardonnay and Semillon-Sauvignon may be, these duets aren't half as intriguing as a solo performance. It may not always come off, but Semillon is potentially one of the most thrilling of all the white varietals. I've been mad about it ever since I first encountered the extraordinary Semillons of the Hunter Valley in Australia - the wines that Aussie wine writer Max Allen recently described as "an absolute bloody national treasure".
The blending tradition which has blurred Semillon's identity is long established. This, after all, is the grape which Bordeaux has typically combined with Sauvignon Blanc to make both its aristocratic dry whites (such as Graves) and great sweet wines (such as Sauternes). Pure Semillon, as a stand-alone wine, is a New World phenomenon. Nothing else about it is new. It's been around for centuries - mainly in Chile, South Africa and Australia. South Africa has fallen rather dramatically out of the picture, however. Semillon now accounts for less than one per cent of its total vineyard plantings, compared with 93 per cent in 1822; a figure so astonishing that we can only hope the Oxford Companion to Wine isn't guilty of a misprint.
Although it was Australia's main white grape before Chardonnay fever struck, Semillon remained in obscurity for an eternity. Right up to the 1980s, it was labelled "Chablis" or "White Burgundy" or "Hunter Riesling" - anything, in fact, but Semillon. But even then, committed producers such as McWilliams and Tyrrells recognised that they had an extraordinary wine on their hands - one that could be drunk early or kept to age for 10, even 20 years, developing gloriously complex flavours without losing its freshness. For me, Hunter Semillons remain the ultimate - the benchmark against which examples from everywhere else are measured. But maybe that's as unfair as comparing all sparkling wines to champagne.
So there are two styles of Semillon - young ones and older ones. In its youth, this wine can be attractive but it's pretty straightforward stuff - fresh, certainly; maybe smelling of grass or gooseberries or lime but without any great depth. At the age of about two, it closes up and becomes downright unpleasant. Then, at around six years of age (or less in warmer regions), it begins to develop into a rich, golden wine like no other. Smelling and tasting like lemon curd on toast, it feels light in the mouth, despite those bold flavours, leaving behind a deliciously fresh tang. High acidity often makes young Semillons taste tart, but is the magic ingredient that makes them live for years.
Hunter Semillons are low in alcohol (usually 11 - 12 per cent - a relief, with so many turbo-charged wines around), and aren't put anywhere near oak barrels. Elsewhere, practice varies. In warmer areas, ripe, full-flavoured grapes may cope well enough with a touch of spicy oak. Alcohol levels will often be higher in these wines from hotter spots. You really have to taste any versions you can get your hands on and see which styles you like. Some of the cheaper Chilean Semillons on the Irish market are confected and pretty forgettable - at least in the latest vintages I've tried. Some oaky, high-alcohol Australians are a bit hard to take. That doesn't leave an enormous choice, but I hope you'll persevere.
Now to the fun bit: which food to pair with Semillon, to help it to taste its best. Light, young Semillons go well with fish, or something like a chicken salad. Young but slightly richer ones, with a touch of oak, go really well with fish in a buttery sauce (or fish pie); they are also terrific with spicy Thai pork or chicken. For an aged Semillon, I can't think of anything nicer than a honeyroast chicken with nutty, golden skin.
In case you're lucky enough to be going to the Olympics - or doing your wine shopping somewhere Semillon is prized - here are a few Hunter versions worth pouncing on: Brokenwood; Lindemans; Karl Stockhausen (from Briar Ridge); Rothbury Brokenback; Andrew Margan; Tower; Mount Pleasant Lovedale. If you happen to have £45 to spare, the remarkable Tyrrells Private Bin Vat 1 Semillon 1992 is a treat well worth trying here in restaurants.