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Under the Microscope

As a topic, it has split the wine community. As a choice, it has baffled consumers. SALLY EASTON explores the pros and cons of the various bottle closures

You can’t pick up a piece of wine literature these days without there being some comment or other about closures – those things we stick in or on the top

of the bottle to keep the wine from coming out. Such a simple thing. Or so you’d think.

The closure debate is one of the fiercest and most prolific in the industry. What are the best ways of preserving wine quality and style exactly as the winemaker intends, and getting it to the consumer in that pristine condition?

Let’s not forget: the reason we have so many different types of closures for our wines is because of faults that appear in wine. Sometimes this comes through poor closure application, sometimes because the closure adds something to, or takes away something from, the wine.

The most notable fault is TCA (2,4,6 trichloroanisole) taint. We used to call this cork taint, but we now know TCA is ubiquitous and is found in a range of sources: cardboard, wood, tap water, as well as cork. It is a musty, damp, dank aroma and bitter taste. At its mildest the wine is faintly dull and lacking aroma, as if the fruit has been stripped away.

In response to this and other wine faults – oxidation (vinegary), reduction (rotten eggs and stink-bomb smelly) and leakage – the industry developed a raft of closure options (see right). And while some of these closure types deal effectively with TCA, all of them are implicated to varying degrees in some of the other wine faults.

Supermarkets as gatekeepers?

We buy the vast majority of our wines from supermarkets. Like producers, they want to offer wine exactly as they bought it – no TCA taint, no vinegary oxidation, no stinky reduction. Tesco has taken an innovative leap by choosing to stopper wines under screwcap. In April 2002 it launched 30 wines under screwcap, 4% of its wine range. It was potentially a risky strategy, given what the industry knew about consumer resistance to this type of closure. Yet the wines have been so successful that Tesco is now committed to having 50% of its range under screwcap by next year. Helen McGinn, PR & product development manager for wine, says: ‘The reason for the move was simple: better-quality wines. Without an answer to TCA we had no alternative but to explore other methods of sealing our wines. There are plenty of options available, but the convenience for consumers and performance of screwcaps makes it the obvious choice for a preferred closure to natural cork.’

Sainsbury’s Lucy Egerton says: ‘Each closure has its own advantages and disadvantages so we consider these before making a decision for each wine. We use screwcaps, synthetics and natural corks. We are including details of the type of closure on the back label.’

Tellingly, when the Sainsbury’s team asked for a well-known Southern French Chardonnay brand to be closed with synthetic rather than natural cork, Sainsbury’s saw a 90% reduction in the number of customer complaints over three months on this wine.

Simon Thorpe MW, one of Waitrose’s buyers, is particularly upbeat when it comes to screwcaps: ‘We are very positive about the impact of Stelvin [screwcap] on a range of wines. There are a number of qualitative advantages, and our customers have embraced the concept. We have been selling Petit Chablis with Stelvin for two years and have experienced sales well in excess of our forecast, and no adverse comments about the closure type.’

He believes we will see more wines closed with Stelvin in the future. ‘This increase is likely to be at the expense of wines closed with synthetics, which we have found are less popular with our customers, and which we feel dumb down the aromatic character found in easy drinking red and white wines.’

Marks & Spencer ‘believe it is important to have a choice of closures and to use the most appropriate for each wine. To help customers make their selection, the stopper type is indicated on each wine’s back label.’ They use most closure types, except technical corks. M&S wine technologist Sam Harrop MW explains: ‘About 65% of our range is under natural cork, from about 75% 18 months ago; 5% are screwcap; 30% synthetic. We only use plastic closures on wines that are meant to be consumed within 12 months of the vintage.’

can a wine be screwed?

Screwcaps have garnered an immense amount of press coverage, and up until very recently pretty much all of it was positive. Now some people are wondering if the screwcap seals too tightly, somehow resulting in reduction issues – that stink bomb odour.

The screwcap revolution was driven by high-quality Australian and New Zealand Riesling and Sauvignon Blanc producers, fed up with persistent TCA in their wines. Michael Brajkovich MW of Kumeu River is a leading light, sealing both reds and whites with screwcap. There has been virtually no consumer resistance in New Zealand and Brajkovich estimates one third of the entire New Zealand wine production might be stoppered using screwcap this year – that from a standing start in 2000.

Of the reductive issue, Brajkovich says: ‘I have not seen it in our, or any other, wine sealed with a screwcap. The same with oxidation. We’ve had the odd leaker (one in several tens of thousands), and the number of leakers is several orders of magnitude lower than with corks. I really think all of these issues are red herrings that are blown out of all proportion, and rank as miniscule in importance compared to the problems associated with corks.’

Harrop is more circumspect: ‘As exciting as screwcap technology is, there are still many unanswered questions. It is not the solution to every single grape variety or wine style. Winemaking techniques need to vary by variety and style to optimise the performance of screwcap.’

The elasticity and compressibility of cork makes it an ideal closure. It’s inconsistency and the TCA issue make it an unacceptable closure. Synthetics are generally suitable for young wines, consumed within 18–24 months of bottling; after which the risk of oxidation increases. Screwcaps seem to be flavour of the month but may be experiencing some teething problems, leading to occasional oxidation, leakage and reduction. The next generation of technical corks, using the proprietary processing methods developed by cork producers, are providing the next revolution in the closure debate – potential consistency and addressing of the TCA issue. The closure debate is wine history in the making.

Sally Easton is a freelance wine writer, consultant and educator

Written by Sally Easton

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