Bottle stopper proves a glass act

Now, however, there is a third way. Glass.

The German company Alcoa has produced a new stopper named Vino-Lok which it claims will retain the romantic and aesthetic connotations of cork as well as protecting the wine from possible contamination.

The device is made up of a glass bung surrounded by a plastic membrane and held in place with an aluminium cap. According to its makers, it is 100 per cent neutral, resealable and recyclable.

The move has won popular support across Europe, with one premium German producer, Schloss Vollrads, already "corking" its wine with it.

Rowald Hepp, Schloss Vollrads’s winemaker, is confident the firm has found the right closure and intends to put at least 50 per cent of its 2004 production under the new stopper.

According to Hans-Joachim Binz, the managing director of Wineconsale, the exporters of the Schloss Vollrads range, the estate is planning to put its first wines under glass stopper from the 2004 vintage and then hopes to bottle the majority of the range under glass in the following year.

"We, like everyone else, have had problems with natural cork but we didn’t want to just follow the New World and go down the Stelvin route. We wanted to do something different," said Mr Binz.

"The best closure for wine is not cork, not synthetic cork and not Stelvin. It is glass."

The stoppers cost slightly more than the best natural corks but Alcoa predicts the price will go down as production goes up. Several German and Alsace producers - including JB Becker and the eminent Rheingau producer Weingut Robert Weil - are already interested.

When a wine is corked, it is tainted by a mould known as TCA-2,4,6 trichloroanisole - or TCA, to its enemies. TCA usually develops in the bark but contamination can come from corks, barrels, other cooperage or even, apparently, from wood within the cellar including walls or beams.

In wine, TCA affects about 5 per cent of all bottles sealed with a natural cork, rendering them less enjoyable, at best, or undrinkable, at worst. The easiest way to spot a corked wine is when it develops a musty, dirty dish-cloth odour.

But corked wine is not the only problem. If the cork is faulty, it can let in air, thus oxidising the wine. And as cork is a natural product, with natural variations, bottle 111 might end up tasting different from 110 and 112 because a different piece of cork was used to seal each one.

Many in the wine industry argue that screw caps make functional sense, but risk turning the sector into a commodity; a bit like canned or keg beer did to cask ale.

Screw caps will never be a complete substitute for cork, particularly in hotels, restaurants and cafes, but will be essential for brand ubiquity, consistency, quality and reliability. And, of course, they are cheaper.

The obvious advantages of Vino-Lok and screwcaps include the elimination of cork taint and oxidation, wines that taste fresher and livelier, prolonged and controlled aging, consistency of aging; ease of opening; resealability; and the confidence when pouring wine that it will be in pristine condition.

Jancis Robinson, the author of The Oxford Companion to Wine, said she thought they were great and much more attractive than other alternatives to cork that have been touted.

Ms Robinson said: "There is a nice affinity between wine and glass and as far as I can tell they do the job very well.

"But although I have written that they are a great idea, I have yet to see one other than a photograph. But they are much more dignified than screwcaps and they are very distinctive for wine."

Asked if she thought it could be used for aged wine she replied: "I don’t see why not."

Alex Bruce, the Scottish director for Friarwood wine merchants, in Edinburgh, also welcomed the measure.

Mr Bruce said: "Screw caps are all very well, but for the wine producer, one has to change the style of wine depending on the closure one is using as wine will develop with a cork far differently than it develops with a screwcap or other closure.

"A wine that has been made and aged for five years with a screwcap will be a very different wine that has been aged with a cork.

"In short, one has to change the method of making wine in order to retain some kind of similar characteristics. But it is important to add that it does not necessarily make the wine better or worse, it just changes the taste of the wine significantly."

The cork industry must have been highly delighted with press coverage of Wine Intelligence’s recent research into UK consumers’ attitudes to wine closures.

Most reports focused on the fact that 60 per cent of the 1,151 respondents said they actively did not like screwcaps, while 99 per cent had a positive or neutral attitude towards traditional cork closures.

"Consumers are not ready to give up their corks," concluded Wine Intelligence.

In the UK, the supermarket chain Tesco looked at Vino-Lok last year but decided it wasn’t for them, not least because the company is very publicly committed to screwcap and has spent millions persuading its suppliers to switch from cork.

But there were other concerns, said Andrew Gale, Tesco’s technical manager: "Our main worry was that it was glass-to-glass. Does it form a proper seal, and does it get glass into the bottle?" he said.

He added that due diligence - the supermarket’s duty of care to its customers - required they be absolutely certain a product was safe before using it.

Portugal produces more than half the world’s cork, with 85 per cent of it being used in bottles. Environmentalists fear a drop in production will cause farmers to replace their cork oaks with pines and other crops.

This could spell disaster for the wildlife which thrives among the two million acres of oak forests in the southern province of Alentejo.