By now most wine buyers are completely at home with all the major varietals. Shelves in supermarkets and off-licenses are filled with bottles that proclaim their variety on the label - Cabernet Sauvignon, Chardonnay, Merlot and Sauvignon Blanc, so you could be forgiven for thinking that that's where the range of varietals comes to an end. Yet the range of grape varieties available to the wine-grower is huge - every traditional wine-growing area across Europe has its own favourite, but these localised grape varieties are hardly household names.

Apart from the big four, there are other varieties vying for pole position, varieties such as Riesling and Semillon for white wines, and Pinot Noir for reds. Riesling and Pinot Noir are often marketed as varietals, but Semillon tends to make its appearance in blends, which may explain why it's less well known than the others.

It's home is in France's south-west, in Bordeaux and its environs. It's traditional use has been twofold: firstly it's blended with Sauvignon Blanc for Bordeaux whites, and secondly because of its propensity to rot, it's used for the great dessert wines of Barsac and Sauternes. The rot in question here is the 'noble rot', a fungal infection with the name of 'botrytis' that has the effect of shrivelling the grapes by extracting their moisture content. A bunch of botrytis infected grapes is a depressing sight - the fruit reduced to tiny berry-sized balls, the whole bunch covered in a grey beard of mould. You'd wonder about the thought processes of the person who first looked at this and thought 'I must make a wine out of that.' But what the rot does, is leave an intensely concentrated grape, and it's that concentration of flavours and sugars that makes a good Sauternes or Barsac so wonderful.

Outside of France the Semillon has never made large inroads in new plantings, for the most part it's been planted only in small parcels for blending purposes. But it has made a home for itself in Australia, particularly in the Hunter Valley. Here the style is dry table wines, and these Semillon wines age remarkably well in the bottle, ageing slowly into complex and lush wines. Outside of the Hunter Valley the Semillon is also fairly well planted, but it's most frequently encountered when blended with the Sauvignon Blanc, just as in the traditional Bordeaux blend. This particular combination works very well in Australian examples, the Semillon contributing a crisp, citric bite to the resulting wine, and some can be truly stunning.

Wine of the Week

Pierro Semillon / Sauvignon Blanc 2002.

Michael Peterkin is the owner and winemaker of this estate in Margaret River, where his surname has been reinterpreted as the 'Pierrot' character of the Commedia dell'Arte tradition, which you'll see on the label. There is a very small proportion of Chardonnay in this blend, acknowledged in the letters 'LTC', which can be found on the label and which stand for 'les trois cepages'. This is a very elegant wine in which the fruit and the acidity are well balanced. Above average in price, but well above average in quality.
Available from Wines Direct, €17.75. Tel. 044 40634