KATHRYN McWHIRTER ON CORKS

GRAPEVINE

IF THE finest corks from the bark of cork oak trees are the caviare of wine bottle stoppers, screw-caps are the lump-fish roe fit only for plonk. Such is the lore we have grown up with. But scientists would disagree. Probably one in 20 of all bottles of wine stoppered with a real cork is "corked", tainted by a musty by-product of mould growth, though wine companies spend a fortune on checking them. There's a further catch to real corks: if they dry out, they let in air, which spoils the wine.

Screw-caps (the best type, at least) are odour-free and air tight. (It's a myth that wine benefits in bottle by "breathing" through the cork). They can keep wine in perfect condition for 10-12 years, according to Professor Terry Lee of the Australian Wine Research Institute. The screw cap "equalled or excelled cork in all trials in Australia".

On the basis of these findings, the respected Australian firm, Penfolds, will be testing our reaction later this year to a good wine under screw cap, with a label explaining the advantages. If we buy it, we won't be the first. The Japanese and the Swiss have been converts for years. One in five bottles of Swiss wine (which is all expensive) is screw-capped. The Swiss have almost done away with preservatives in their wine, thanks to the screw cap.

Maybe the new-age British wine drinkers, feet on the ground, will be just as pragmatic. They have raised no objections to the plastic "corks" that have recently been cautiously infiltrating British wine shelves in a first bid by wine retailers to eliminate the problem of tainted natural corks. Pioneers Marks & Spencer, Sainsbury's and Safeway report "no comment" from the public.

Of the two types of plastic "cork" here now, the most attractive are the golden-yellow "SupremeCorqs" you can buy stoppering the peachy, lemony 1995 Safeway Australian Semillon-Chardonnay (pounds 3.99), or the black version of the same "corq" in the blackcurranty 1994 Isla Negra Chilean Red (pounds 3.99 Waitrose, pounds 4.25 Oddbins). SupremeCorqs are made in the USA from an elastic plastic (a thermoplastic elastomer) that is also used to make artificial heart valves.

These "corqs" are squashy, waxy and not too difficult to get back into the bottle. They are as elastic as real cork, seal the bottle well, and can't dry out, so bottles don't need to be stored on their sides. You pull them out with an ordinary cork screw, get the usual pop, and if you are anything like me, you might even keep them to play with - they look and feel so nice. In America (where 60 wineries are using SupremeCorqs and hundreds more are testing them) one winery uses white, blue, purple, tangerine, yellow and forest green versions. Drinkers collect them, according to satisfied winemaker Laurent Montalieu.

The snag is the cost. SupremeCorq is as expensive as a long, top-quality natural cork (around 15p a pull). British supermarkets are used to paying around 1-2p each for stumpy "agglomerate corks", made from tiny bits of waste natural cork, stuck together, or 2-4p for lowish grade, stumpy, natural corks cut from one piece. Near this price, their only plastic option is the short French "cork" called "Tage", at just over 2p. The Tage "cork", made of EVA (ethyl vinyl acetate), is natural cork coloured, with mock veining; it comes out on your cork screw with a pop, and you can store it upright. But it feels much harder, and is difficult to push back into an unfinished bottle.

This is the "cork" Marks & Spencer now uses in 15 of its wines (20 by the summer), and Sainsbury's in 12 by the summer. My favourites among the Tage-stoppered wines are crisp, lemony, floral 1995 Cotes de Gascogne, Azcue (pounds 3.49 Marks & Spencer) and 1995 Domaine Mandeville Viognier (pounds 4.99 Marks & Spencer), a spicy wine with lovely peach and apricot flavours. The producers say you can store Tage-stoppered wines for two to three years; they are conducting longer-term trials. Most supermarket wines are drunk within days or weeks. "Tage are slightly more expensive," says Alan Cheeseman, departmental director, wines and spirits at Sainsbury's. "But that's nothing against complaints about corked wine. The corkiness problem is frightening, absolutely frightening."