From the bark of the cork oak (Quercus suber), comes the cork, a lightweight, porous and waterproof material, three qualities that make it the ideal solution for closing and sealing a bottle of wine.
Its origin dates back to the mid-s. XVIII and its use spread rapidly, thanks to Dom Pérignon, a monk born in the ancient province of Champagne (France). The monk realized that the cork fits perfectly the neck of the bottle and, most important, it prevents the carbon dioxide (produced by a secondary fermentation in the bottle) from sending the cap flying, when expanding and contracting due to temperature changes.
The external climatic conditions, however, have some influence in the state of the cork: the lack of humidity dries it out and causes pores to appear thus risking the wine to oxidize and decay faster. Conversely, too much moisture can produce mould on top of the cork.
Even so, the cork is still the perfect material, especially for those wines destined to lay down in a cellar. These wines have been aging for a long time and need some rest in the bottle, to finish assembling all the elements and achieve a better balance. In this case, the cork is essential since it makes micro oxygenation possible, thus helping the wine in a slow, more or less controlled, evolution.
So, for a bottle of wines, cork has become the ideal companion, although it also has its drawbacks, such as contamination by TCA (trichloro), a possible risk if the cork is not of good quality.
Currently, the trend is to replace cork stoppers with other materials in young wines, like the silicon and the screw cap, with good results so far. But when it comes to great wines, with many months of aging, the cork still rules atop.