The Interesting Story of Where Cork Comes From
Cork comes from the bark of an evergreen oak tree. It drops acorns and grows a thick bark which is known as a cork tree. These trees are primarily found in Mediterranean countries such as Portugal, Spain, and Italy. The bark is harvested every 9-12 years after the bark regrows, and the process does not harm the tree. It is a renewable resource and biodegradable. Portugal produces 60% of cork in the world. Spain is 2nd producing half of this. Out of all the trees in Portugal, 30% of them are cork. Cork oaks are the only oak whose bark regenerates in this fashion, making this a very special tree.
The European cork industry produces 300,000 tonnes (a tonne = 2204 pounds) of cork a year, with a value of $1.6 billion and employs around 30,000 people.
The trees must first mature for 25 years before the bark can be harvested for its first or ‘virgin cork’ harvest and then 9-12 years must pass before it can be processed again. This can go on for 200 years!
The cork farmers will use white paint to mark the tree with the last number of the current year so it’s clear to know the next time a harvest can be done. This is how they protect the species. The cork is so sacred that laws protecting the cork have been in place since the 1200s.
A cork oak lives for about 150-200 years on average meaning that it will be harvested about 15 times over its lifecycle. The trees grow well in poor sandy soil.
Knowing how high up to harvest the bark is determined by the diameter of the tree. If the tree is 1 meter in diameter (or 3.28 feet), you can harvest 3 meters (or 9.8 feet) of the height of the tree.
Cork farmers know exactly how to remove the cork so as not to damage the tree. The process is labor intensive and delicate. The stripping of the trees is done every summer mid-May to mid-August when the trees go through their growth spurts. The bark is carefully split off the tree. Handheld cork axes are used to remove the cork from the trunk. After harvesting, the tree has a gnarly, reddish look to it.
The cork farmers will transport these large, curved slabs of bark on trucks to processing plants. They are pressed under concrete slabs for 6 months. Then the bark is sterilized using a big boiler. There they are further compressed and graded for their uses. Wine corks require the highest grade. One wine producer said that the cork can even be more than the cost of the bottle.
38-year-old bark, roughly the third harvest, is when the bark becomes of high enough quality to produce these wine stoppers. One cork tree can produce about 4000 corks.
To make the bottle stoppers we know so well, slices of cork are boiled to remove impurities, like the chemicals that cause cork taint, and dried until they reach the optimum texture to be pressed into bottles.
Fun Possible Fact: The 18th century French monk, Dom Perignon is said to have revived the use of cork due to the smell and taste. Corks were originally used for wine, but cork taint would strongly affect the smell and flavor of the wine. Oily rags were then used to seal the opening. Olive oil to be exact. Since the glass bottles were blown by hand, making precise bottle openings was difficult. The spongy cork is expandable and will fill uneven bottle tops, so they went back to cork. Problem solved! Well mostly. Cork taint can still be present today. Cork taint occurs when a chemical called TCA creates an undesirable smell or taste found in a bottle of wine especially after aging or opening. The cork stopper is usually blamed over the wooden barrel or storage conditions. Improvements have been made to help avoid cork taint over the years, but it still can happen.
So, is there anything that you can do about cork taint in the glass of wine you hold in your hands? You could try using plastic cling film also known as food plastic wrap. And not just any type. It has to have the correct synthetic polymers to be capable of removing TCA from a liquid. In fact, prolonged exposure to the right plastic wrap can remove as much as 82% of TCA molecules from a wine. Here’s how to do it. Pour the wine into a jug. Ball up a wad of plastic wrap, drop it in, and stir. The bad stuff will get caught in the plastic wrap making your wine drinkable again. Other than that, the sad truth is that there are no other ways to remove the cork taint. Lucky for us, this doesn’t happen much anymore.
Cork is used for making different things depending on the age of the tree. A younger tree’s harvest is used for flooring and bulletin boards. As the cork grows and the structure tightens, the cork is best used for wine stops.
Cork is also used to create containers and covers for food, soundproofing in music studios, purses, mouse pads, hot plates, shoes and clothes. It is also used for multiple items such as stoppers, discs, different types of floats, shoe soles, printing paper, bathmats, table mats, yoga mats, hat bands, fishing rod handles, cigarette tips, and different kinds of packing.
Cork wool is produced for cushions and mattresses and granulated cork is used as insulating material in shipbuilding, or a protective packing for fruit and eggs, or as tubing for plastic substances.
Another Fun Fact: The biggest cork tree in the world lives in the southern area of Portugal, in the town of Aguas de Moura. It is called the Sobreiro Monumental (Monumental Cork Oak). It is 234 years old and 52 feet tall and with a trunk that requires at least 5 people to circle it. It has been considered a National Monument since 1988, and the Guinness Book of Records states it as the largest and oldest. This tree is known to harvest 100,000 corks. It is nicknamed The Whistler because of the many birds which nest in the branches. It has been harvested since the 1820s and continues to produce.
And that’s my story about cork. As I researched this, I found myself digging deeper into it. I’ve always liked cork things. I already have cork shoes and a bulletin board, so I’m thinking cork purses are next…