New world wine makers are set to take on the status quo with more than just the contents of their bottles - the tops are also undergoing a revolution. Dave Robertson reports on why a group of winemakers in the Clare Valley in South Australia have turned their backs on the traditional cork in favour of the screw cap.

Risking a snobbish backlash from punters, a group of Australian winemakers has just been joined by a group of New Zealanders in taking a plunge with screw caps, or stelvins as they are also called. And those involved believe they are trailblazing a path that will shortly be followed by the major wine makers.

Jeff Grosset, owner of Grosset Wines in the Clare Valley, moved 80% of its 9000 case production to screw caps

A loose association of thirty Kiwi winemakers officially launched their screw cap bottles on earlier this month and have appointed a local master of wine to sell the idea internationally.

"We risked a lot doing this but it has paid off," says Jeff Grosset, owner of Grosset Wines in the Clare Valley, which moved 80% of its 9000 case production to screw caps. Grosset's Rieslings are rated among the best in Australia and continue to get rave reviews, particularly among Sydney's sophisticated restaurant crowd.

"If we waited for the larger players to go ahead nothing would ever happen. They are advised by marketing people who say the public isn't ready," he adds.

Southcorp, which makes Australia's premium Penfolds range, admits it is not considering a change from traditional cork. It did offer UK consumers a limited run with screw caps with a questionnaire attached but the responses were not favourable and the issue is not under consideration.

2000 Dry Riesling

The New Zealanders believe that their excellence in Sauvignon Blanc and Riesling will benefit from moving to caps because even a small amount of cork tainting can influence the quality of these wines.

The first premium winemaker to move to the stelvin top was Kim Crawford of Marlborough who released his 2000 Dry Riesling this month. Others include Lawson's Dry Hills, Jackson Estate and Forrest Estate.

The Australian Wine Research Institute released results last month that show that caps are the best way to stopper a bottle. The institute took a standard A$14 (US$7) Semillon wine from South Australia and bottled it in 1999 with 14 different types of stopper.

Scientists then used a range of criteria to test the effectiveness of the stoppers. The three main tests were tainting, extraction force and sulphur dioxide retention.

Tainting is the main reason alternatives have been developed. Corked wine is believed to affect about 5% of all bottles and occurs when microorganisms in the natural cork combine with chemicals in the wine to produce a foul smell and taste.

But the most important criteria turned out to be sulphur dioxide and ascorbic acid levels as these are vital elements in giving wine its distinctive taste. As SO2 is lost the wine suffers "browning" and oxidation.

So although many consumers are still not ready for the change science is on the side of the screw cap.

The results are easy to read but for legal reasons the Institute will not grade the 14 stoppers. Natural cork performed about average in extraction and SO2 retention but suffers from losing one bottle in 20 through tainting.

Technical corks, a mix of synthetic and natural cork like a Champagne stopper, performed better while fully synthetic corks performed well in SO2 retention and, being rubber, suffered no tainting. But they are the hardest to remove from the bottle.

The shock winner was the screw cap, which was easy to get off, retained the most SO2 and had virtually no tainting - miniscule levels of a rubber-like aroma were detected.

"If wine makers are looking at ultimate freshness and eliminating tainting you'd chose the screw cap"
Peter Godden

The study will continue for another ten years but already the results have interested many in the wine industry.

"We've been overwhelmed with calls from all over the world," said Peter Godden, who is leading the project.

"If wine makers are looking at ultimate freshness and eliminating tainting you'd chose the screw cap. There is a perception issue with the cap as 20 or 30 years ago they were used on low price wines and fortified wines so there is a perception that the cap is only good for this level of quality."

But wine experts believe that the snobbishness that might prevent many people buying a screw cap will alter as soon as top reviewers start backing the change.

"Wine does collect a snob value as people think they are connoisseurs and that's why they're against caps. But most aren't confident of their views so when one of the big name wine reviewers like [American] Robert Parker says its okay it'll take off," says Andrew Caillard, director of Langtons Fine Wine Auctions in Sydney.