It's deathless prose: 52 per cent cabernet sauvignon, 45 per cent merlot and 3 per cent petit verdot. The label tells you everything and nothing about the 2007 Château Brown, Pessac-Léognan, £25.99, Soho Wine Supply (020-7636 8490), an enticingly spicy Bordeaux. It's the 3 per cent petit verdot that's intriguing.
How can such a tiny percentage make any difference when the major proportions are cabernet and merlot? The answer is seasoning. Similar principles apply to the 2006 Château Romefort, £9.99, buy two = £7.99, Majestic, a modern claret – only here it's the 7 per cent cabernet franc that brings a freshness to the blackcurranty merlot and cabernet sauvignon.
Bordeaux is a region in which blends of different grapes each vie for space in the final blend. The late-ripening petit verdot is always in a minor key, while cabernet franc often dominates on the Right Bank. The Bordelais have cleverly learnt not to put all their eggs in one basket.
In Burgundy, the opposite applies. Here growers have found that pinot noir needs no other company. A wine such as the bright 2010 Mercurey Vieilles Vignes, from Domaine Raquillet, £18.95, Lea & Sandeman, relies on pure pinot noir for its sumptuous mulberry fruitiness.
The Rhône's north is pure syrah territory for the pepper and spice characters of a wine such as the textured 2009 Domaine Collonge Crozes Hermitage, £12.99, Marks & Spencer. Its Mediterranean south blunts the syrah's edge, bringing the grenache and mourvèdre grapes into focus in the spicy 2005 Gigondas, Clos des Cazaux, La Tour Sarrazine, £16, Goedhuis & Co (020-7793 7900).
Languedoc likes blends, too. In the 2007 Domaine La Borie Blanche Terroirs d'Altitude, Minervois la Livinière, £9.99, buy two = £7.99, Majestic, it's the grenache at just 10 per cent that adds the white pepper touches to the dominant syrah and mourvèdre. The New World knows such rules, so the juicy 2009 Willunga 100 The Olive Branch Grenache, £9.99, Sainsbury's, stands on its own one foot.
Rioja allows tempranillo both on its own as in the vivid 2007 Cosme Palacio Tinto, £9.99, Morrisons, or seasoned with mazuelo and graciano in the case of the 2007 Bodegas Ruconia Tubal, Rioja Crianza, £16.50, Lea & Sandeman. Chianti has jettisoned its legal requirement for white grapes in favour of pure sangiovese and you'll find few sleeker examples than Fontodi's 2008 Chianti Classico, £18.50-£21.95, Cooden Cellars (01323 649 663), Noel Young (01223 844744).