Jan 28, 2011

‘The Death of the Cork’ – original NZSCWSI members (from left to right) Dr John Forrest, John Stichbury, John Belsham and the late Ross Lawson conduct a funeral for the cork in 2001.

As we peruse today’s crowded wine shelves, it is difficult to ignore the proliferation of screwcaps. With over 90% of New Zealand wine now sealed this way, the eradication of cork and other closures in the local wine industry is in sight. The impetus for change arose from the New Zealand Screwcap Wine Seal Initiative established in early 2001, following the brave move to screwcaps by Clare Valley winemakers disillusioned with cork’s inconsistency ruining their fine Rieslings.

New Zealand isn’t alone, with global interest in screwcaps also expanding rapidly in the last ten years with wine producers, wine trade and wine consumers unable to disregard the compelling research confirming them as the superior wine closure. Of the seven billion wine bottles sealed worldwide each year, it is suggested the number using screwcaps has grown from an estimated 100 million ten years ago to almost three billion this year. While traditionalists may still be reluctant to embrace them, there is now plenty of scientific evidence that indicates money spent on wine sealed with anything but a screwcap is a game of risk.

From a scientific perspective, the Australian Wine Research Institute proved screwcaps to be the superior wine seal by confirming what many had known for some time – that cork was inconsistent as regards oxygen ingress and that synthetic closures (with the highest permeability) were only suitable for wines destined to be drunk almost immediately. Peter Godden, AWRI’s Group Manager said, “The biggest issue for any form of cork closure is variability - the wines sealed with screwcaps were extremely consistent bottle to bottle and no other closure achieved results even similar.”

An activity demonstrating screwcap’s superiority, and cork’s inferiority, was undertaken at the London Wine Trade Fair in 2002 when the NZSCWSI showed to what extent cork could contaminate wine. As John Belsham of Foxes Island explains, “We ran a very simple trial of putting corks into glasses of acidified water. There was a varying degree of colour and flavour taint in all of them, except one - the glass containing no cork.” This simple yet very graphic experiment clearly demonstrated cork’s unsuitability as a consistent and neutral wine closure.

For those doubting the aging ability of wine under screwcap and who believe wine requires oxygen to mature, much research has been conducted that concurs with Professor Emile Peynaud, a French oenologist and researcher credited with revolutionising winemaking in the latter half of the 20th century. He explained, “It is the opposite of oxidation, a process of reduction, or asphyxia by which wine develops in the bottle.”

James Halliday, one of Australia’s leading wine commentators agrees: “Looking back over the last decade of the NZSCWSI (and the similarly timed all-important move to screwcaps by the Riesling makers of the Clare Valley) my only regret is that the migration to screwcaps did not occur ten years earlier. Many of the wines in my cellar would be in far better condition had this occurred then”.

Matthew Jukes, author and wine writer for the UK’s Daily Mail is confident that acceptance is now a given. “Nobody blinks these days in restaurants when a sommelier unscrews a bottle – and the sommelier is delighted too, because he knows that he won’t have to run back to the cellar to get another because the first one’s corked!”

For the consumer, the significant efforts of research facilities, wine producers and closure companies, not to mention the huge impetus created by the New Zealand Screwcap Wine Seal Initiative have ensured quality wine has never been easier to purchase. With so many bottles vying for space on those congested shelves and still much uncertainty about how to choose, at least those sealed with a screwcap can provide assurance that the wine is exactly as the producer created it.

For further information please contact Belinda Jackson via email: or phone: 64 27 444 8 666