Definition - What does Cork mean?
Cork is a light, water-resistant, buoyant, insulating, elastic and compressible form of bark tissue usually derived from a tree called Cork Oak. The multiple properties of cork make it a useful substance for many industries: fishing, flooring and wine making. The water-resistant and elastic nature of cork makes it a suitable choice for wine bottle closures.
WineFrog explains Cork
The cork used as wine stoppers is produced from the trunks of the cork oak tree, after the tree is 25 years old. Since the process involves only stripping the barks and not cutting down the tree, the cork industry does not contribute towards deforestation and is considered an environment friendly industry. Portugal and Spain are the highest producers of cork.
Cork is believed to have been in use since the late 17th century. The cellular wall structures of cork allow it to compress and expand easily. Additionally, it acts as an insulator and does not absorb the wine content. Given the practicality, cork wine closures are the preferred method of sealing wine bottles, with 60% of wine bottles produced world-wide having been produced with cork stoppers.
Even with other alternatives, such as plastic stoppers, available and studies questioning the benefits of cork usage, cork closures continue to remain popular for their traditional value, practicality and environmentally friendly production.