Sauce: cheap's not always cheerfulJoanna Simon

The shelves are alive with the sound of wine prices being slashed. But there’s a problem with wine sales: unlike jeans, which you can try on, you rarely get to taste the wine before you shell out, unless there’s time to buy a bottle to try at home first.

Still, there are things you can watch for. Top of the list are tired wines. Rosés don’t improve with keeping, and the vast majority of whites don’t either. As a rough guide, the cheaper the white wine, the less likely it is to improve — that’s also a broadly useful guide for reds. Prosecco and cava should be drunk young; if you think they’ve been hanging about, pass by.

Know your grape varieties. The unfairly stigmatised riesling ages well — both southern hemisphere and European — whereas sauvignon, pinot grigio and viognier fade quickly. Among reds, pinot noir is short-lived, especially new-world pinot; cabernet sauvignon and syrah/shiraz last longer. And remember that wines from the southern hemisphere are about six months older than those from the same year in Europe and America. As for “mystery cases”, if the wines were really good, the sellers would identify them.

2008 Finest Tapiwey Sauvignon Blanc, £3.99

Great half-price offer on this zesty, gooseberry-scented Chilean sauvignon (Tesco).

2007 La Sabrosita Old Vine Garnacha, £4.39

Big, spicy, juicy Spanish red. Good value even at its usual price of £5.49 (Marks & Spencer).

2006 Richard Leroy Anjou Le Clos des Rouliers, £14.82

Superb dry white Loire to drink now or lay down. Price held for January only (Vine Trail, 0117 921 1770).

Wine bluff

“Italy has the most organic vineyards of any country”

Anorak fact

Nearly 5% of Italy’s vineyards are organic, whereas Australia and South Africa score low, with less than 1%