How Cork is Made

Monday, July 23rd, 2007 at 12:00 am

wine corkMost of us know that corks are included in wine bottles. They are a natural part of the wine bottle which serves the purpose of containing wine as well as keeping the air out of the bottle. However, have you ever wondered what really makes up a simple cork and how is it made? Wonder no more as we reveal to you the technicalities of producing a cork. So sit back and read on what it really take to produce a seemingly trivial but essential part of wine.

The material where cork is made from is a subset of standard cork tissue which is harvested for commercial use. It primarily comes from the Cork oak tree whose scientific name is Quercus suber. One interesting fact is that Portugal produces almost 50% of the cork in the world. This particularly increasing demand for cork product gives Portugal the lead in both quality and quantity of cork production.

A good thing about cork trees is that it can be harvested more or less a dozen times during its lifetime. This is because Cork trees live from the range of 150-250 years. Virgin cork or "male cork" is the first cork which is cut from typically 25-year-old trees. The second harvest happens around 10-12 years after the first because it is this time that the cork tree needs to wait.

In order to harvest a cork tree, one needs very skilled labor simply because a special axe is used to cut into the bark and then it is used as a lever to ever so gently pry the cork off the tree. That cork is peeled off in large panels from the main sections of the trunk which includes the large branches. After that, a third of the bark can be harvested from the tree at any one time.

Because of this very specific and careful process, cork harvesting is done entirely without machinery in order to maximize the quality and quantity of the cork as well as maintaining the cork tree’s health and ability to be harvested again and again.  

Because corks are made of the bark which is harvested from living, uncut trees, European environmentalists have advocated the use of cork over other, synthetic alternatives. The sustainability of its production as well as the ease of recycling products made from cork are its two most distinctive aspects.

Quality corks are quite expensive so those wines which are less expensive have already switched to plastic stoppers or screw caps. The downside to this is that screw caps will give the wine more exposure to air, thus speeding up the oxidation process. Screw caps and other closures are also a bad idea if you want to keep your wine quality high because it encourages the levels of SO2 to go up. This chemical gives wine the smell of rotten egg.

Because of this, wine connoisseurs still prefer corks over any other closure. Because of this, it is very important that one understands the value of corks. More than anything, they keep wine from smelling bad and they preserve the freshness for many years.