Tag Archives: Cork Trees

Uncorking Cork

By Rebeccah Marsters

With the abundance of information on wine labels these days, it’s a testament to the time-honored tradition of opening a bottle that we find no instructions for uncorking. Imagine the classic scenario: lights are low, the music plays, you use an elegant silver corkscrew to ease open a bottle of wine. The gentle ‘thwup’ meets your ears, and two glasses are at the ready. The truth is, once the cork is dislodged, it’s typically forgotten as we move on to more important things- namely, experiencing the wine. But take a minute to examine and appreciate that diminutive brown cylinder before you cast it aside and begin to pour; chances are that without its presence, wine would not exist as we know it today.

An inspection of the cork makes apparent that it’s a natural product- the irregular composition and color are your first clues, and a sniff reveals a scent not of factories and polymers, but of something organic and of the earth. Indeed, cork is the bark of the Quercus suber tree, or the cork oak. Indigenous to the hot, arid climates of Spain, North Africa, and Portugal, the latter of the three today accounts for about half of cork production worldwide, and the cork industry in that country is so vital to the economy that it has been under strict regulation for centuries. Recognizing what an important resource it was, the European Cork Industry Federation has even developed a code of practice for its production.

Why so much hoopla over something that quite literally ‘grows on trees’? The harvesting of cork is a complex process. A cork oak does not produce usable cork until about 25 years of age and then can only be harvested once every nine years. This resting period in between harvest allows for the outer layer of ‘bark’ to regenerate and this is only one of the many complexities involved in the process.

Harvesting cork is both labor intensive and time consuming, requiring skilled workers to carefully strip the trees and stack the planks of cork outside where they will cure in the sun, rain, and fresh air for up to six months. The cork panels are then cleaned, usually in a process involving a boiling water bath, fungicide, and scraping, after which they are deposited in a cellar to dry before they are finally deemed adequate for their intended use. In the case of wine stoppers, which account for about two-thirds of the cork industry, the planks are cut to a thickness equal to the desired length of the cork and perfect cylinders are punched out.

So how did this little piece of Portuguese tree bark find its way into your bottle of chardonnay? The use of cork as a plug dates back to ancient Egypt and Greece, and excavations have discovered amphorae with cork stoppers still intact at such illustrious sites as Pompeii and Athens. Despite these auspicious beginnings, wine was not a bottle-based industry for centuries; instead, transactions involved a merchant drawing wine from a barrel into receptacles provided by the buyer. Jumping ahead to the 1600s, we come upon the cellar master of Hautvillers Abbey in France- a gentleman known as Dom Pérignon- who was vexed when his champagne bottles kept popping open. The wooden stoppers wrapped in oil-soaked rags that were common at the time could not stand up to the increased pressure of the effervescence in his precious bubbly, and his decision to replace these crude closures with cylinders of cork was more consequential than he would ever know. The 1700s saw mass production of glass bottles, meaning that with a uniform neck and opening, utilizing a similarly uniform product to seal the bottle was only logical. In 1750 the first cork stopper factory opened in Spain, and for the first time in history, aging wine in the bottle became a realistic endeavor. With a cork in place, a small amount of gas exchange occurs, but the wine is fully protected, and can develop and mature for decades.

Given the labor required to produce corks and the fact that they have been in use for thousands of years, it’s surprising that no one has come up with a ‘better way’. However, the qualities that make cork such an effective stopper are inherent in the material itself, thus no amount of development or modernization can best it. Cork is light, impermeable, chemically inert, and resistant to wear, rot, fire, and temperature extremes. Its compressibility (a cork can be squeezed to half its width) combined with its ‘elastic memory’ means that it exerts even pressure against the inside of the bottle neck, and can compensate for tiny imperfections in the surface of the glass which might otherwise allow unwanted transfer with the exterior environment.

Going back to our scenario in the opening paragraph, lets imagine you’ve opened your wine, tipped the juice into your glasses, and lowered your nose to the bowl to inhale a deep whiff of…wet dog. Some alternatively describe it as moldy newspaper or damp basement, but it’s universally accepted that whatever the sensory manifestation, the smell of cork taint is unpleasant. We’ve all heard someone refer to a bottle of wine as ‘corked’, and the technical explanation of this has to do with a fungus-produced compound called 2,4,6-trichloroanisole, or TCA, that grows in cork fibers and is transferred into the wine. The compound enters the cork either through environmental pollution or as a result of chemicals used in the sterilization process, and these are what cause the TCA. Despite efforts from both US importers and Portuguese producers to control the condition, between three and seven percent of all bottles with natural corks are affected. This has led many wineries to go the route of alternative closures- either the synthetic cork or screwcaps. While both cheaper and easier to produce than natural corks, there is a considerable populace who staunchly opposes their use.

Let’s return once more to our scenario and consider for a moment replacing the charmingly antiquated act of uncorking a bottle of wine with that of simply unscrewing a cap. In the wine world, the cork represents so much more than utility; it is a part of the romance and appeal of wine as both a beverage and an historical entity, and many people are not willing to forgo that. Screwcaps also have a structural impact on wine, as they don’t provide the oxygen exchange allowed by real cork. This is perfectly suitable for the 70 percent of wine that’s consumed within three days of purchase; however wines meant to develop in the bottle require the real thing. Not only has cork proven its worth for hundreds of years, but it’s the most environmentally sound choice as well. The trees and forests from where cork originates are home to endemic wildlife and provide a livelihood for farmers and their families. Taking into account that wine is an industry and should consider functionality above all, it’s nonetheless hard to ignore these factors.

There will always be new trends and innovations in every sector of the beverage industry, but with such an auspicious timeline up until now, there’s little danger of any of these passing fancies supplanting natural cork as the wine closure of choice. Few natural products are as aptly suited for their use as cork. Whether for the science of oxidative versus reductive maturation, or the flourish of wielding a corkscrew and deftly opening a bottle, there is no lack of justification for keeping the cork firmly in place, so to speak. Whatever happens in the future, the cork has played an undeniably vital role in making wine what it is today, and we can all agree to drink to that.

After receiving her degree in Art History from the University of Vermont, Rebeccah Marsters decided to go to culinary school where she completed an associate’s degree in Culinary Arts at Johnson & Wales in North Carolina.  After, she began an internship at America’s Test Kitchen (ATK) in Brookline, MA and was later hired full-time at ATK and now work as Assistant Test Cook for Cook’s Country magazine where I develop and test recipes and produce the food for the magazine’s photo shoots.

1 Comment

Filed under Smart Tastes