Synthetic corks, made from plastic, debuted in 90's with the main benefit of preventing cork taint associated with natural cork stoppers and caused by the chemical TCA. While natural cork lost substantial market share to plastic stoppers during this era, cork producers countered by stepping up their manufacturing process to significantly reduce the opportunities for TCA contamination by refining and improving their production process, and have successfully reduced the cork taint rate from what was once as high as 5% - 10% of bottles, down to a incidence rate as low as 1%. With the improvements across the industry, cork taint has been significantly reduced. The main benefit of using synthetic cork or screw tops these days is price: they're substantially cheaper to produce. But at what environmental cost? Here are some of the green points of natural cork production.
A Green Crop: Cork grows on trees in Mediterranean climates like Spain, Portgual, Algeria, Morocco, Italy, Tunisia and France. Cork trees grow with zero inputs: no pesticides, no irrigation, and no pruning required. In Portugal, which is the number one country for cork production, cork harvesting is highly regulated by the government. Trees aren't harvested until 25 years of age, and then only every 9 years (by law). After a harvest, trees remain living, and usually stick around for another 170 years or more. Trees are harvested by stripping the outer layer of skin with a small hatchet by trained workers who are paid a good living wage. It does not harm the tree in any way.
Green Processing with Energy from Production Waste: Cork is then taken to factories where it is dried, boiled, and turned into cork stoppers or various other products. The amazing thing about these factories is that up to 90% of the energy used in processing cork is made from burning cork dust, a byproduct of production. Of the cork that is pulled off the tree, absolutely none of it goes to waste. And for those who might think there aren't enough cork trees to go around, there are. Contrary to the belief of some, demand for cork does not exceed available cork tree reserves in the Mediterranean area.
Environmental Impact: Synthetic corks are made from petroleum based plastic. While they're recyclable (#7 here in the U.S.), not many people know this. Additionally, the energy inputs to make synthetic cork or metal twist of corks are substantially higher than those of natural cork. In addition to natural cork being biodegradable, there are natural cork recycling programs around the U.S. designed at ensuring natural cork doesn't reach the landfill either. Natural cork wine stoppers also make great craft items (See Top 10 Holiday Uses for Wine Corks). Wine Quality: Even for those not concerned with the environment, natural cork has benefits to how a wine tastes. Natural cork does not change the taste of the wine. In fact, synthetic cork is only recommended for wines to be stored and drunk within 5 years. Even twist off wine tops require a small piece of plastic on the inside to form a good seal - go ahead, and look the next time you twist one off. The idea of having plastic in contact with a beverage designed for human consumption, alcohol none the less, for a substantial amount of time simply seems like a bad idea after our experience with BPA.
Other Cork Products: Beyond bottle stoppers, cork is used in a wide range of other products. From flooring, to flooring underlayment, to sustainable aircraft insulation, cork has a wide range of other natural qualities that make it a superior product for use in these applications. Some of the benefits of cork, beyond sustainability, are the following:
- Naturally cushioning (Used in food-beds and shoes for a reason)
- Durable (Just think Birkenstocks or the floor in the library of Congress which is made from cork)
- Insulating (Space shuttles use cork as an insulator for its light weight and insulating ability. See GizMag's article on Aerocork here).
(Images: Trent Johnson. Originally published 2010-08-12)