No one is completely sure who first came up with the idea for cork wine stoppers, though legend holds that it was the 17th-century monk Dom Pérignon. Perhaps he does deserve the credit; perhaps some other cellar master was the first to abandon convention and seal his glass wine bottles with cork stoppers over wooden plugs. Regardless of who created the wine cork, the invention would go on to become wildly successful: For the past 400 years, cork has been the preferred material for wine closures.

The idea caught on because it was a good one—cork resists moisture and rotting, it helps wine age, and it provides an effective leak-proof seal. At the beginning of the 21st century, though, cork experienced a fall from grace, as the issue of “cork taint”—a phenomenon associated with spoiled wine—became more prevalent. The primary cause of cork taint is the presence of the chemical compound 2,4,6-trichloroanisole (TCA). But TCA isn’t limited to cork; it’s also found naturally in wood, water, soil, fruit and vegetables. This means that other factors, including the storage of wine in wooden barrels, can contribute to wine spoilage. But because cork and wine have long been so inseparable, and because cork is a known source for TCA, the phenomenon of wine spoilage was named for the ubiquitous cork stopper. It was a nightmare for the cork industry.  

How common was it? In 2005, Wine Spectator magazine tested 2,800 bottles of wine for TCA. Seven percent of the bottles were contaminated. For consumers, it seemed the chances of buying spoiled wine were relatively low. But for a winemaker, whose name and reputation are on the line with every sip, a single bad bottle could damage the brand’s reputation and undermine the entire business.

As a result, many vintners began abandoning cork in favor of alternative closures, like aluminum screw caps and plastic plugs, which also had the added benefit of lower cost. Importing cork from the Mediterranean can be expensive, especially for wineries in New Zealand and Australia; by 2010, most wineries in those countries had switched to screw-cap closures, which were also gaining prominence across the world.

Though it has recaptured some market share in recent years, the cork industry is now fighting against the newly discovered appeal of plastic and aluminum. A wine-shop manager told me screw caps have “just about taken over the market,” especially with lower-priced wines. Screw caps are just easier to use. “And people like that,” he said. “Even wine drinkers.” Aluminum screw caps once sealed primarily cheap malt liquors and quart bottles of beer; today they cap 20 percent of the world’s table wines. Plastic stoppers have also surged in popularity, now accounting for 10 percent of the wine-closure market.  By some estimates, cork has lost nearly 40 percent of the wine-closure market since the late 1980s, a loss most apparent in low-priced ($10 and under) wines.

Much of cork’s current struggle can be attributed to one group in particular: Millennial wine drinkers, a generation that has less of an allegiance to traditional cork closures. A 2012 report by the Wine Market Council, a nonprofit association of grape growers, wine producers, importers, and other affiliated businesses, revealed that 65 percent of older Millennials (over the age of 25) drink wine daily or several times a week; half of younger Millennials (21-25) fell into the same category. The report also revealed that roughly two-thirds of Millennials “frequently or occasionally” purchase unfamiliar brands of wine, and 60 percent admitted to being swayed by “fun and contemporary-looking” labels. The type of bottle closure, by contrast, isn’t an important factor in purchasing decisions—and when it is, the lack of need for a corkscrew may well be an enticement.

Patrick Spencer, the executive director of the Cork Forest Conservation Alliance, an organization working to preserve the Mediterranean cork forests and their inhabitants, believes that misinformation about cork—prevalent at a time when many Millennials came of drinking age—helped erode the material’s popularity. “At the turn of the century, probably 85 percent of all wines were still sealed with natural cork,” Spencer told me. “This is also the time when the rumors about cutting the cork trees down, cork shortage, and wine spoilage of 10 percent (due to natural corks) began to surface.”

“You have a perfect storm for this age gravitating toward alternative closures,” he concluded.

* * *

Before cork taint frightened so many winemakers into abandoning cork, the material had helped to successfully preserve fine wines for centuries. In fact, the 2010 discovery of 168 bottles of champagne in a Baltic Sea shipwreck was a testament to this ability: The food biochemist who led the scientific team that tested the 170-year-old champagne called it “incredible.”

Cork’s sealing qualities stem from its natural compressibility—a result of cork’s unique cell structure, which flexes under pressure while allowing trapped air to function as a counter-pressure. This feature allows a cork to be pressed into a smaller physical space and yet spring back to its original form when removed. Cork’s compressibility is perhaps most apparent when uncorking a wine bottle, but it can also be felt when wearing a pair of cork-soled shoes, for example, or when walking on cork floors. Step after step, cork absorbs the pressure and then instantly springs back to its original form, no worse for the wear.

Following the cork-taint scare, the cork industry set out to improve both its product and its image. Cork producers invested in new equipment and worked to refine production techniques, contributing to a sharp decline in tainted wine. Recent tests by the Cork Quality Council show a 95 percent reduction in TCA since 2001.

They also began promoting cork’s environmental benefits, noting that the production of cork wine stoppers is a “carbon-negative” process: The seven million acres of cork forest around the Mediterranean offset 20 million tons of CO2 each year, and the trees are not cut down to produce cork closures—because only the bark is removed, the production of cork products is completely sustainable.

Once stripped from the tree, the cork bark grows back and is harvested again a decade later. This process is repeated over and over throughout the tree’s lifetime, which may exceed 200 years. Stripping a cork oak of its bark also enhances its ability to absorb carbon dioxide; in Portugal alone, cork trees help offset over 10 million tons of CO2 every year.

The cork forests of Portugal, the world’s leading supplier of cork, feature some of the greatest biodiversity in the world. According to the World Wildlife Fund, these forests contain the highest levels of plant diversity found anywhere in the world—reaching levels of 135 species per square meter—while also providing a habitat for endangered animal species like the Iberian lynx and Barbary deer. Demand for cork products, especially wine stoppers, helps preserve the cork forests, which would otherwise be neglected or replaced with non-native trees.

What’s more, healthy, well-managed cork forests benefit the economies around them—cork production provides some of the world’s last, well-paying agricultural jobs, supporting, directly and indirectly, an estimated 100,000 people in Portugal, Spain, Italy, France, Morocco, Tunisia, and Algeria. The industry employs roughly 35,000 people in the Iberian Peninsula, alone, and contributes approximately 10 million Euros (more than $11 million dollars) annually to the rural economy of Morocco.

The damage control appears to be working, at least in part. Recently, I asked the manager of my favorite bottle shop if anyone bought cork anymore.

He nodded as he peered through tiny, wire-rimmed spectacles at his store’s considerable wine inventory. “The restaurants still buy traditional closures because customers love the ceremony of having their wine uncorked,” he said. “It’s part of the experience.”

Even as cork producers rely on customers’ desire for that traditional experience, the industry is being bolstered by new applications for the material. Demand for cork is growing, even beyond the wine industry—in home décor and building materials, in jewelry and clothing, in automotive design. Cork has even found its way into the aviation industry, where it’s being used in the construction of lightweight aircraft components.

But still, no application is more important to cork’s success than its use for wine closures, which accounts for 70 percent of all cork produced today. While cork appeals to customers—especially older customers—who perceive it as an indicator of a higher-quality wine, vintners and cork producers believe that younger consumers will develop a loyalty to cork stoppers as they learn more about the material’s environmental benefits.

“Consumer demand has proven time and time again that it has the power to move an industry to make decisions that the public requests,” Patrick Spencer said. “We firmly believe that if we can be successful in our education, cork recycling, and cork forest eco-tourism programs, the public will demand natural cork and force a move by wineries away from their trend of alternative closures.”

The industry has a powerful ally to help it push its education campaign forward. As an advocate for cork-forest conservation, the World Wildlife Fund is working to protect these landscapes by promoting products from sustainably managed cork-oak forests. And if choosing cork really can help save a tree, that’s something worth drinking to.


This article appears courtesy of Object Lessons.


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