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Turning the screw on closures

Published:  23 July, 2008

Cork producers have found a possible saviour in the recent eco-debate to arrest the move by buyers to synthetics and screwcaps.

But will it be enough to overcome accusations of unreliability and taint? Rebecca Gibb looks at the latest developments in the ongoing debate about the best way to stopper a bottle.


While TCA has been reduced, though not eliminated, there are other key factors in the closures debate, including rate of oxygen ingress and consistency. Paul Sanders, technical manager and winemaker for Bottle Green, which supplies many of the UK multiples, says: "At the premium end natural corks are good, but there's too much variability at the lower end with oxidation."

Chablis producer Michel Laroche, a prominent screwcap supporter who famously put his Grand Cru wines under Stelvin five years ago, believes TCA is no longer the main issue. "The problem with cork is not TCA but oxidation - within five to 10 years my wines were oxidised under cork. I have the feeling that the wines are going to last twice as long under screwcap."

Screwcaps have been accused of encouraging reduction, with 2.2% - or one in 50 - wines found to have been affected at the International Wine Challenge. Bruno di Saizieu at Alcan remains unconcerned.

"Reduction is not a problem. You have reduced wine with cork as well as screwcaps. It all depends on the liner." The inside liner controls the rate at which oxygen reaches the wine and Alcan currently produces two kinds. It is working on a "new generation" of Stelvin with differentliners to suit different markets, due on the market by the end of 2008. Di Saizieu says: "The Japanese prefer their Chardonnay more oxidised than the Americans so winemakers can decide on their liner by market."

Some say that reduction is not a closures issue but a winemaking issue. Oeneo's Dean Banister admits: "A lot of winemakers went into screwcaps without thinking about adjusting their winemaking. Some wines have a tendency to be reductive. It's not a grape thing - it's a vineyard thing."

You'd expect a winemaker to know his or her vineyard well enough to know whether their wines had reductive tendencies and adjust their wines accordingly but it is still an issue. So why, in 2007, are they still getting it wrong?