The Cork – The Unsung Hero of Wine

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(Stored correctly, meaning temperature & humidity, this cork is over 7 years old)


The history of using corks for closure on wine bottles dates back to the late 1600’s. Prior to that everything from cloth, leather, wax and glass stoppers were used. Why do you want a good seal? One is to retard the chemical reaction between fruit acids and alcohol. The second one is the oxidation process which needs to be curbed or suspended. But total suspension is as bad as too much oxygen.

Some of the interesting facts about cork are:

• The higher quality of corks allow approximately 1 milligram of oxygen to enter the bottle each year. Why is this important? Air allows the sulfites to be removed that are added in the
bottling process to keep the wine fresh and not have harming effects from oxidation.

• Cork harvested off Oak trees needs to be at least 25 years old before being considered top grade.

• The cork from Oak trees is known as Quercus Suber. Cork Oak trees grow to 60 feet in height and 12 feet in circumference. The trees are harvested once every 9 years.

• After harvest the cork needs to be “dried out” which takes between 1 to 6 months.

• After the drying process, the cork is boiled to sterilize and clean it. This process also “softens” the cork material.

• The major issue with cork is TCA or tricholoroanisole. This is recognized as the smell of wine as being rotten eggs or moldy sneakers!

• Approximately 70% of worldwide wine production uses cork to seal their bottles.

• Portugal provides almost 50% of the world’s cork and Spain 31%. The balance is spread between Morocco, Algeria, Tunisia, France and Italy.

• Only about 1 to 2 percent of wines today are “corked” or affected by TCA. Some figures show as much as 3-5% can be “corked”.

• The standard cork that fits a typical 750ml bottle of wine is ¾ of an inch. Various lengths are also available.

Alternative methods from glass to plastic to synthetic to manufactured corks are being used but the long term viability is yet to be determined. Similar with screw caps. That said with most wine being consumed within seven to ten days of purchase, synthetic, glass and screw caps are gaining some ground. This actually helps the cork industry as it is a renewable and limited resource.

So the next time you pop the cork out of the bottle, think about its long history and its vital function in delivering you a wonderful wine.





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