Cork is the outer bark of the cork oak tree, Quercus Suber, which grows mainly in the Mediterranean region. The bark is a vegetal tissue composed of an agglomeration of cells filled with a gaseous mixture similar to air and lined with alternating layers of cellulose and suberin. Cork's elasticity, combined with its near-impermeability, makes it the perfect material for making bottle stoppers, floor tiles, insulation sheets, bulletin boards and other similar products. Because of its remarkable qualities, cork is used in high-tech applications including car engines, dam mechanisms and airport runways. The aeronautics has used cork as a thermal insulator in space shuttles.

The use of cork as a raw material dates back to Phoenician and Greek times. Cork began to become known all over the world as an effective bottle stopper for wine. In fact, cork is the only material that makes a perfect seal during the ageing of the wine.

Today, cork is a valuable resource for Portugal, representing one of its most important export products.