Top ten trends of the last ten years: 8. The wine closure debate

In our third installment of the greatest changes in drinks since db was launched in July 2002, we consider the importance of the closure debate.

The closure debate has remained heated over the past ten years

Throughout db’s history if there’s one issue which has proved consistently inflammatory, it is how best to seal wine.

Early last decade, New World producers were understandably irate over the high incidence of 2,4,6-trichloroanisole (TCA) in their wines, blamed entirely on faulty corks.

New Zealand turned to screwcaps, where usage increased from 1% in 2001 to 70% by 2004. Indeed, the country can be credited for making the screwcap almost the default closure for aromatic white wines worldwide.

But it wasn’t only the New World that went against cork; a major signal that the traditional closure may be in trouble came with Domaine Laroche’s decision to seal its Chardonnays from the 2001 vintage in Chablis with screwcaps – including its grands crus.

But just how bad was TCA in finished wine (whether from corks or sources such as barrels or storage containers)? Domaine Laroche claimed 10% of their wines were spoiled, while 2004’s International Wine Challenge in the UK had figures showing 4.9% of the 11,000 bottles opened had perceptible TCA taint.

In 2005 a Wine Spectator blind tasting of 2,800 bottles produced a headline-grabbing figure of 7% for wine taint.

Such evidence inspired the invention of various techniques to guarantee TCA-free corks, from steam cleaning to more complex processes, such as supercritical fluid extraction.

At the same time, plastic corks became mainstream.

However, early examples frustrated consumers who couldn’t remove them from corkscrews, and the weak seal between plastic and glass also led to high levels of oxygen ingress after 18 months, as highlighted by an Australian Wine Research Institute survey in 2001.

This was not a problem for naturally elastic cork.

As the level of TCA in wines sealed under cork began to drop, the debate shifted to other properties of the various closures.

OTR studies showed the differences in oxygen permeability in screwcaps, depending on the lining, with Saratin the least permeable

Under particular scrutiny was the oxygen transmission rate (OTR) of screwcaps and natural cork, as well as so-called technical corks, and increasingly sophisticated synthetic closures, particularly from Nomacork.

Soon db was writing not so much about TCA, but OTRs and finally, TPO (total package oxygen), as it became clear that oxygen pick-up during bottling was a crucial part of any potential problems.

Then there were the environmental implications of different closures, and the carbon footprint of a cork versus a screwcap became another area of interest.

Indeed, as db completes its decade reporting on the issues, which it has done extensively with the expert help of Sally Easton MW and Dr Jamie Goode, it’s interesting to note a minor comeback for cork.

Indeed, Peter Gago, head winemaker at Penfold’s, admitted during an event after this year’s London International Wine Fair, that levels of TCA in his wines were down to 1%, or, he explained, the same percentage that are prematurely oxidised due to mechanical damage to screwcaps.


6 Responses to “Top ten trends of the last ten years: 8. The wine closure debate”

  1. Paul Tudor MW says:

    Once again, the other major driving factor here in NZ is not mentioned. Random oxidation was a major problem, not just for Sauvignon Blanc, but other varieties and styles. Also, because we are on the other side of the world from Spain and Portugal, it is my hunch that the quality of cork being sent here was not necessarily as high as it was in neighbouring countries.

  2. Hard to see how the significant efforts of Tesco (for whom I worked at the time) in the introduction of screwcaps can be written out of history. Ann-Marie Bostock and her team put the screwcapped wines on the shelves, a risk that no other major retailer was prepared to take.

    • Patrick Schmitt says:

      Well said Philip and sorry for not mentioning in the piece. Was it early 2003 that Tesco first put screwcaps on the shelves?

  3. Marc R Kauffman, CSW says:

    “A minor comeback for cork”…interesting. Or how about Nomacorc put all the other synthetic corks out of business.
    The debate now is really about what alternative is there between cork and screw caps?

  4. Dagger says:

    Cork taint is often the poster boy of discussion regarding cork vs other closures including screwcaps. But as Paul Tudor rightly mentions, random oxidation is a problem that continues to dog those who bottle white wines under cork. Cork is an inherently variable product. One cork will seal a lot better than another, even if it came from the same grade and batch. It is this variabiltiy in the closing properties of cork that will continue to present its archilles heel. Screw caps are orders of magnitude less variable than cork when it comes to oxygen ingress. I don’t know about everyone else, but when I open a $100+ bottle of White Burgundy I get pretty cross when it is oxidised.

  5. Dagger says:

    Given that 1) Penfolds only bottle their higher end red wines under cork, and 2) presumably they use only the more expensive higher grades of cork for these pricier wines, and 3) they almost certainly do in-house testing of cork batches before use, then a lower failure rate than that found in the general cork population would be the inevitable result, wouldn’t it?

    The author of the article should mention that not all corks are born equal. There are expensive corks and there are cheap ones (and I’m talking within bark cut cork, not composites), so unlike screwcaps, cork quality varies a lot depending on how much you are willing to pay. I would be interested to know how many other winemakers who use the more varied grades of cork think that 1% is reasonable value for taint. And finally, isn’t Penfolds currently trying to position themselves at the ultra-high end of the Chinese market – the one that equates high quality wine with a cork stopper?

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