In the 1600s a Benedictine monk called Dom Perignon observed that wooden stoppers wrapped in oil-soaked rags used to seal bottles often popped out, and so he replaced them with the pieces of cork to seal the sparkling wine.
Cork soon become essential for wine bottling. The world’s first cork stopper factory opened in around 1750, in Anguine (Spain). The best cork comes from Portugal, and the country is the world’s leading cork producer.
The bark of mature cork trees is harvested just once every nine years. Cork trees are not regarded mature enough for bark harvesting until they are at least 25 years old, and the bark itself is not suitable for wine corks until the third harvest. The trees are not cut down, they are harvested, by hand, every 9 years. A cork tree will yield 13 to 18 useful harvests in its lifetime.
The cork may sometimes become contaminated with harmless but foul-smelling TCA thus causing cork taint in wine.
There is no cork shortage; in fact, there is enough cork to close all the bottles of wine produced for the next 100 years.
Below is a very interesting video showing just how cork is harvested off the trees: