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The Cork Closure Makes a Comeback

Once in disgrace, this tiny bark stopper is wooing wine lovers once more

Roger Morris By August 23, 2021
illustration of cork separated from wine bottle
Illustration by Derek Abella.

For more than a hundred years, pulling a cork from a bottle of wine, pouring a splash, swirling the glass, and then inhaling the fruity aromas was the most-honored dining ritual. And then that experience caused wine lovers to turn up their noses — literally.

Doug Frost, a Kansas City Master Sommelier and Master of Wine, remembers one such evening in the 1980s after he organized a special wine tasting. “We opened 36 bottles,” he says. “Two different vintages of Ridge Monte Bello were corked. Two different bottlings of J.J. Prüm Wehlener Sonnenuhr Auslese were corked, one of those a 1983 Goldkapsel Auslese. And a Léoville Barton 1985 was corked — that was significant because it was a three-liter bottle!”

For the cork-producing barons of Portugal and the Mediterranean region, the period from the early 1980s through the first decade of this century were the worst of times, happening during the best of times. Just as new consumers from China to Chicago were causing wine production to explode, up to 7%  of all bottles were corked — one whose wine stinks of a musty smell called “cork taint,” caused by a naturally occurring molecule called 2.4,6-trichloroanisole and related compounds, which are sometimes formed in cork bark. When present, TCA will ruin the wine.

The demise of cork

Some thought cork taint was merely the wine’s natural taste. Master Sommelier Evan Goldstein, president of Full Circle Wine Solutions in San Francisco, says that when he was co-owner and sommelier of a restaurant in the 1980s, a couple ordered a $900 bottle of old Montrachet. “The cork reeked of cork taint, but I decided to pour them each a taste,” Goldstein says. “The man asked the woman what she thought, and she said, ‘It’s the best bottle of wine I’ve ever tasted!’ I’m still not sure I did the right thing.”

By the turn of the century, the message was out of the bottle — cork, the preferred closure for wine since the ancient Greeks used it to seal amphorae, was no longer a reliable wine bottle stopper. So serious was the issue, that in 2000, a group of Australian winemakers decided to abandon cork altogether in favor of screw-caps — even though there weren’t any screw-cap suppliers in Australia at the time. A year later, 30 New Zealand wineries banded together to form the Screwcap Initiative. Less than 10 years later, more than 90% of New Zealand wine was being bottled under screw-cap. 

In the U.S., the screw-cap was traditionally associated with cheap wines. But even producers of expensive wines began to abandon ship. After PlumpJack co-owner Gordon Getty opened a prized bottle of corked 1947 Cheval Blanc, the Napa Valley winery proclaimed half of its 1997 Napa Valley Reserve Cabernet Sauvignon would have cork closures and half screw-caps. Many producers just decided to make the switch to metal tops completely. By 2005, 4.7 billion plastic stoppers were being used in bottles, and by 2010 only 47% of wine bottles sold in the U.S. were finished with cork stoppers.

“It was a very rough period,” says Carlos de Jesus, who heads marketing and communications for industry leader Amorim. “The Portuguese cork industry was investing millions in research, but it would take years for the world to see the results. It was all very frustrating.”

Yet 10 years later, 66% of wines sold today in the U.S. for $6 or more are sealed with cork, as are 90% of those priced over $20. What happened?

“The cork reeked of cork taint, but I decided to pour them each a taste. The man asked the woman what she thought, and she said, ‘It’s the best bottle of wine I’ve ever tasted!’”

Technical leaps

First, the alternatives proved far from perfect. Plastic stoppers were an environmental nightmare for disposal. Although screw-caps preserve a wine’s freshness longer, some winemakers and drinkers preferred the slower evolution of a wine under cork. Additionally, wine made with little oxygen in the process could become stinky or reductive when sealed in metal. Moreover, the popular Coravin preservation system needs expensive secondary caps to work with screw-capped bottles.

Those in the cork industry followed two different approaches to the TCA problem. Diam, a French company founded in 2004, took natural cork bark, finely ground it, cleansed it of any TCA by using fluid, high-pressure carbon dioxide, then reformed it into stoppers using natural glues. These became known as composite or technical corks.

Amorim, M.A. Silva, and other members of APCOR — the Portuguese cork association — continued to work with cork the traditional way in which large strips of cork bark are harvested in cork oak forests and are cleaned, dried, and cured. Machines then punch out cork closures in different sizes and grades. As cork is harvested from mature trees about every nine years, a cork oak produces multiple cork crops. 

APCOR members first sought ways, such as gas chromatography, to detect and reject tainted corks at the factory, a process they say they perfected just a few years ago, a temporary solution on the way to totally eliminating TCA-contaminated corks.

APCOR also started a public education campaign in 2006, explaining cork is natural and that cork forests are instrumental in cleansing the atmosphere of excess carbon dioxide. “The sustainability message really took off in 2008 and 2009,” de Jesus says, noting that in recent years the cork sustainability message has been so widely embraced that “the public owns it.”

This year, consulting firm KPMG, proclaimed M.A. Silva’s cork operations even to be carbon negative. Old corks can also be recycled for other uses. 

Meanwhile, prominent customers began returning to cork, such as Chablis producer Domaine Laroche in 2016 after a decade of using screw-caps. “With a good cork selection, we have the right combination of oxygen, and we have a slow evolution in the wines,” says technical director Grégory Viennois. “I think that’s why we like to open old bottles. We have a new combination of molecules and new aromas, and we have the incredible mystery and aging of fine wines.”

In California’s Lake County, Clay Shannon of Shannon Ridge winery said he switched back to cork because, “The customer tells us that they prefer cork over screw-caps, so the decision to switch was easy.” He also said cork fit in with his winery’s strong sustainability profile. “When it comes to renewable, you can’t beat Mother Nature.”

Finally, this February, Amorim, which produces 5.5 billion wine stoppers annually, declared victory in the 30-year war — claiming that cork taint has been completely eliminated from its production through use of a steam process, and surveys showed customer confidence was restored. Has TCA disappeared? Certainly not from wines of older vintages, and not every cork producer has the resources or willpower of Silva and Amorim to make guarantees. Additionally, TCA can occur in wineries practicing poor hygiene; even vineyards can become infected, although rarely.

Interestingly, the folks at Diam technical corks think the story of cork getting its groove back is just beginning. “Winemakers are now experimenting with our corks because they allow different degrees of oxygen transfer to the wines at a consistent rate,” says Yoann Canovas, the company’s regional technical manager. In other words, the Diam cork range allows winemakers to test their wines to age differently depending on the cork.

For cork makers and tradition-loving wine drinkers everywhere, the romance is back.