Cork is the bark of a tree resident in the south of Portugal called cork oak, "sobreiro" in portuguese(Quercus Suber L.), being a 100% natural material. At a microscopic level, cork is a vegetable tissue composed of cells filled with air and coated in with suberina, lignin and other minority compounds such as polysaccharides, ceroides and tannins. In this way,cork can also be used as an insulating material.
The process of dehulling, "descortiçamento" in portuguese, consists in the removal of the cork from the cork oak, since this is the only tree whose bark is self-regenerating. Traditional and traditional techniques are applied in the clearing, being a very arduous process due to high temperatures that may reach around 40 ºC and the ground conditions. It is possible to do the decortication in the end of spring and beginning of summer because the bark is less adherent to the trunk and the cork tree can be exposed without being damaged due to dry weather and high temperatures. For dehulling, a specific ax is used with a wooden handle and a wedge to lift the cork without ever touching the trunk. The men are responsible for the work with the ax and women for carrying the cork to the place of transport. From each cork oak, an average of 40 to 60 kilos of cork is removed.
The first two cork removals are used for various purposes such as insulation, flooring, construction, fashion, design, health, energy production or in the aerospace industry. The first extracted cork has the designation of "virgin cork", in a process called "desboia" in portuguese. After 9 years, a new extraction of cork can be made and this type of cork is called "secundeira" in portuguese. After another 9 years, the cork with name of "amadia" is obtained and can already be used in stopples because after each extraction the texture of the cork becomes smoother. To know how many years left to the next process of dehulling, the year is marked on the tree with white paint. The leftover cork is used in products that can be made with crushed cork.
After the extraction, the cork acquires a red color that turns to dark brown as the bark regeneration happens. The dehulling process can be carried out about 15 times, since each cork tree lives an average of 150 to 200 years.