Picture, if you will, the following scene.

You are on a date with that special person. You've taken her to a fancy restaurant, complete with candles, and you have a very expensive shiny rock burning a hole in your pocket.

She has ordered a slice of the finest lamb, with a fancy sauce whose name you can't even pronounce. You have ordered a chunk of dead cow, so raw that it still says moo. Thus, after much perusing of the wine list (complete with fake gasps of horror that such a restaurant would even consider offering a Spanish red), you have selected a St-Estèphe, a muscular red ideally suited for the occasion both in taste and in Frenchness.

The sommelier arrives and shows you the bottle. As expected, it is dark green and has a very plain label marked with absolutely no English. You nod, and the foil is deftly removed. Then, with a deft flick of his wrist, the sommelier unscrews the cap.

Corks have been used to seal drink bottles for several millennia, and on all good French wines for at least four hundred years. They are not state of the art technology. They are not, in fact, even particularly good at their job.

When wine is left to age, there is a danger that the cork can become tainted and start producing 2,4,6-trichloroanisole, an unpleasant-tasting chemical that can ruin the wine's flavour. This is the main (but not only) cause of what is known as corked wine.

Estimates as to how much wine is affected by corking vary. For wines that are aged for five years or more, many producers estimate that anywhere up to one bottle in twenty is tainted. The problem is becoming more and more severe, since increased demand for wine has lead to a drop in the availability of high quality cork. Thus, some wine producers are switching to alternatives.

Synthetic cork substitutes are one option. However, as well as being far harder to remove, synthetic corks are generally considered to be not particularly good for stronger wines. A more popular alternative is the screw cap.

Screw caps have been used on some cheap and nasty American wines for a long time. With the quality of the wine not being an issue, little effort was put into making the screw caps any good — so long as they didn't leak, they were considered adequate. More recently, various new world producers have worked hard to create a screw cap that is not only a replacement for but an improvement over corks. Numerous scientific studies have shown that they have succeeded, particularly with the Stelvin brand and imitation styles.

Good screw caps consist of an inert metal covering (often an aluminium alloy) that will not react in any way with the wine in the bottle. Not so good screw caps consist of a not so inert metal covering that gets eaten away by the acidity in the not so good wine in the bottle. A screw cap must be almost or completely air tight — cork allows a very small amount of air circulation, which some consider to be an important part of the ageing process, but any substantial circulation leads to the wine becoming vinegar. Most screw caps also include a tamper evident seal and some form of embossed or printed top.

So if, as proponents have claimed, high quality screw caps provide a cheaper alternative to corks that is less prone to damaging the wine, why are old world wine producers not jumping at the chance to change?

The question is one of image. Decorking a bottle is not as easy as unscrewing it, but it carries with it certain connotation, among these being class, sophistication and romance. Screw caps, on the other hand, are associated with lemonade and the sort of wine that isn't even good enough to be sold in a box. Whilst some Australian and New Zealand producers are trying hard to market the change, French and (to a lesser extent) Italian wine producers are eschewing it, not because of technical reasons, but because of tradition.

It may be that, sooner or later, even the most expensive French wines switch away from corks. However, in an industry where price is still very much governed by an arbitrary set of classifications from 1855, the scenario described is not likely to happen for many decades to come.

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