The cork oak
The bark of the cork oak is composed of micro cells, which are generally of polyhedral form. The inter-cellular spaces are filled with air. The special characteristics of cork and its multiple applications are due to this honeycomb structure and the nature of the cellular membranes.
Lightweight, resistant to wear, impermeable, elastic but of stable size, cork has a perfect capacity for heat insulation and vibration dampening. It has been used in the manufacture of many products, for thousands of years. It is highly ecological.
Segments of bark, as large as possible, are detached with great care, ensuring that the phellogen base is not affected. This layer not only produces the usable material. It also ensures the regrowth of bark of the tree.
The first stripping of cork of young trees can only be carried out when it is at least 25 years old and the perimeter of the trunk reaches 70 cm. The cork obtained from the first stripping is called “male cork”. It is used for low-quality products such as floor tiles, pin-boards, etc.
At the time of the second removal (secundeira), cork is still not yet ready to be made into bottle stoppers. Ripe and perfect “female cork” for wine bottles will not be harvested for another 9 years. So the cork oak must mature for at least 43 years before it can produce cork for wine stoppers.
A bit of history.
The galleons of 16th century, venturing into unexplored seas, were known as “the cork galleons”, so large was the quantity of bonds, benches, trunks, bowls, mess tins, shoes and other objects carved from cork bark.
Seacork’s raw material comes from the cuttings of wine stoppers. The cuttings are reduced to granules and mixed with a special resin. Blocks of cork, which can be cut into sheets of different thicknesses, are compressed at hight atmospheres.
An article in the WWF explains very well the ecological advantages of cork. This article in English reveals to us, in a time when CO² is a real scourge for our climate, that the lifting of cork causes over consumption of 3 to 5 times higher than normal, in order to reconstitute its bark.