Another look at the screwcap vs cork debate

By / Magazine / March 27th, 2018 / 9

In the July/August 2017 issue of Quench, I wrote a column headlined “Screw Cap or Cork” (read it online here), in which I maintained: “The incidence of corked wines is falling, mercifully, as cork producers have become more scrupulous in how they cut the cork trees, dry the bark, punch out the cork lengths and bleach them. But one ‘corked’ wine is one too many when the problem can easily be remedied with a screwcap.”

The article caught the attention of the New York public relations firm that represents the Portuguese Cork Association (APCOR). An account executive emailed me asking if I would like to “engage … in a deeper conversation that sheds light on the new advancements and data that has emerged on natural cork in the last few years.”

In the interests of open-minded journalism, I replied that I would be happy to do so. So, a conference call was set up with Portugal to speak with spokesmen from APCOR and Amorim, the world’s largest producer of cork.

The cork industry worldwide, they informed me, produces 12 billion wine corks annually. Amorim’s share of the market is 4.4 billion pieces. Currently, of the 17.5 to 18 billion bottles of wine produced globally, 12 billion are under cork. Another 4.5 to 4.7 billion are closed with screwcaps with the rest stoppered with plastic corks or glass.

Since the introduction of screwcaps and plastic stoppers, Amorim’s sales of cork have actually increased, I was informed. Using gas chromatography to eliminate the Trichloroanisole that creates cork taint, Amorim’s quality control people can detect the incidence of TCA to 0.5 of a nanogram, a nanogram being one billionth of a gram. Given the introduction of this new technology, Amorim has two insurance companies willing to, “underwrite guarantees bottle by bottle of the non-detectability of TCA … the level of extraction is so high that we are able to offer that guarantee.”

“Wineries all over the world,” their PR representative initially wrote, “are discovering or rediscovering why natural cork is the best fit for their wines.” For example, Penfolds recently said that the company now believes screwcaps are not the best option for its closures, especially for higher-end wines, and that the winery will now focus on cork closures. Penfolds winemaker Peter Gago has also said that “screwcaps are not the future.”

Gago explained the factor underpinning the company’s reinforced interest in cork, especially for higher-end wines, is that the TCA problem has been “partially solved,” and quantified that, “examples of TCA in cork [are] now down to around 1 percent, comparable to the percentage of screwcap-sealed wines that suffer from oxidation, due to mechanical damage of the stoppers.”

I contacted Peter Gago to ask for clarification; I quote his written reply”

“Firstly, my comment that ‘screwcaps are not the future’: I actually regularly state that neither cork nor screwcap are the ultimate closure solution — both are dated! Secondly, since 2004 all Penfolds white wines have been sealed under screwcap for all markets. We actually started bottling whites under screwcap in 1971 (Autumn Riesling) and have been delighted with the results ever since for our white wines. Thirdly, the issue of Penfolds reds bottled under screwcap or cork? Penfolds reds are available under both cork and screwcap, depending upon the market. One exception — Grange (cork in all markets). What we have noticed recently (concurrent to an overt decrease in TCA incidence — our guestimate hovering around 1 percent) is a collector trend towards seeking out our more expensive reds under cork.”

So, the debate continues. I can only hope that the rest of the cork industry is as scrupulous as Amorim in their o-going efforts to eradicate the TCA menace.


Tony Aspler, Order of Canada recipient, has been writing about wine since 1975. He is the author of 18 wine books, including The Wine Atlas of Canada and three wine murder mystery novels. The best concert he ever attended was Rush with the Tragically Hip as the opening band. His favourite comfort food is milk chocolate and his cocktail of choice is a Kir Royale. At home, he drinks wine (lots of wine).

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