Learning about wine, its production, and long history never ceases to fascinate me. My best friend recently visited for dinner and a movie; and of course we sipped a bottle of wine or two. I had previously told him about an artful idea I had that involved used wine bottle cork, so on this particular visit, he brought me a bag full of the bottle corks that he had accumulated. As we were fingering the cork stoppers and reminiscing about the tasty and not-so-tasty wine associated with each cork, a thought popped into my head- what do I really know about cork? I knew a little, but guessed that there were even more interesting details I was no doubt missing out on.
Cork comes from the Quercus suber tree a member of the Oak family and commonly called Cork Oak. These majestic trees grow mainly in regions of Portugal and Spain. In these countries, the Cork Oak is grown for industry purposes such as plugs for wine bottles. But, cork’s fame is not only in connection with wine production. Robert Hooke, a scientist in many fields including chemistry, biology, and physics, studied cork extensively. In 1663, he used the most sophisticated magnifying equipment available, rudimentary by today’s standards, to view cork at a microscopic level. What he discovered and named were cells, a complex and integral part of most life on earth.
Quercus suber trees are planted and allowed to mature approximately 25 years before their first harvest. Once they reach an appropriate age, they can yield a harvest about every 9 to 12 years. The trees are marked with the last year of harvest so the strippers know to allow the tree to recover. In the dry and hot temperatures of these cork bearing regions, workers move from tree to tree stripping large patches of porous bark from the shade-bearing cork trees. Each tree can yield cork for around 200 years producing an average 100 pounds of cork each harvest. However, the amount of cork harvested from a single tree depends on the tree’s size and individual characteristics.
The oldest cork tree known is called the Whistler Tree. This tree has been growing for about 230 years, since 1782. The Whistler Tree gave up its first batch of cork in 1820; its latest harvest in 2000 yielded 1,818 pounds of bark, enough to make over 100,000 wine bottle corks and all from this single tree. By the end of this incredible tree’s life it will have produced enough corks to make over 1 million wine bottle stoppers.
Each layer of cork harvested is nearly 8 inches thick and only about 20% of harvested cork each year is used for wine stoppers. Yet, the wine industry accounts for the majority of profit associated with cork harvest and production. But, with the shift to screw caps, plastic bottles, and boxed wine, what will happen to the cork trees? A thriving industry that employs tens of thousands of people and promotes the preservation of these intriguing trees hangs in the balance.
The main argument against the use of corks in wine bottles is an occurrence known as cork taint. Because cork is so porous, it can accommodate the growth of fungus if not sterilized properly. The moldy taste synonymous with fungal growth can taint or change the intended flavor of the wine rendering it undesirable. Alternatively, many winemakers use cork because of its porous nature citing benefits to the wine such as slight oxygen exposure to promote optimal aging. Additionally, the soft structure of cork allows the material to expand after it’s inserted into the wine bottle thus providing a tight seal against wine leakage. Personally, I enjoy the novelty of a glass bottle and old-fashioned cork. And, I especially like the thought, that in some small way, I’m bonding with such fascinating specimens, the Cork Oak trees.
Guest Post By Sarah Meadows