Cork is the bark of the cork oak tree - Quercus Suber L. - which means that it is 100% natural plant tissue. The cork cells, grouped in a honeycomb structure similar to a beehive, are filled with a mixture of gases that very similar to air, and their walls are primarily covered with suberin (a kind of natural wax) and lignin (a three-dimensional microcell that is resistant to microbiological attacks). Other compounds are identified in its chemical composition, although in less quantity, such as polysaccharides, ceroids and tannins.
It takes 25 years before each cork oak tree can be harvested for the first time and it is only from the third harvest (when the tree is 43 years old) that the cork, then known as amadia cork, will have reached the high standard of quality required for producing cork stoppers. The first two harvests – of “virgin” cork and “secondary” cork –, as well as the cork removed from the base of the tree, becomes the raw material for insulation, flooring and products for areas as diverse as construction, sports, fashion, design, health, energy production and the aerospace industry.
Cork is extracted by highly specialised professionals, always between May and August, when the tree is at its most active phase of growth, which makes it easier to remove the cork without damaging the trunk. Experienced, qualified and careful hands protect both the tree and the cork. After harvesting, each tree is marked with the number of the last digit of the year when the cork was extracted.