Corks for wine are made in cork material coming from the skin of a particular kind of oak called quercus suber. This tree grows in Mediterranean area, north of Africa and south of Europe. The main producers of this material are in Portugal and in the Italian Island called Sardinia. After planting it, this tree needs a lot of years before producing cork, at least 30 years. Then the producers have to take out the cork and throw it away, because the first cut it’s not useful. Then the tree needs 10 more year to produce enough cork again and this second cut is useful to produce corks for bottles . then producers can take out cork from the tree every 10 years. So it’s easily understandable why cork it’s such a expensive material.
so far cork is still the best material for wines that need to rest in bottle for several years. Not only because it’s easily compressible to put it into the bottle neck, and because it can fit the bottle perfectly, sealing it from external dangerous things, but also because its tiny holes let a small quantity of oxygen enter the bottle which can make the flavor of the wine smoother and better. A different material with bigger holes can’t be good because too much oxygen could destroy the wine. On the other side, although it’s really good for young wines that should be drunk in few years, a totally closed cork like plastic one can’t make the wine better during years.


Corks for high quality wines are made in a single piece of cork, For sparkling wines and medium quality wines are composed of particles. More economic wines have corks made of granular particles, also called "technical corks".


Since middle of 1990, some branded started to use plastic closures instead of cork material in order to avoid the cork taint in wines. This defect is due to trichloroanisole (TCA)  which is produced by a fungus called Armillaria Mellea which lives in the base of cork trees. A high number of wine bottles can have this problem, around 5-7% of bottles. The characteristic of this defect it’s a strong smell of wet newspaper, wet dog, which make the wine undrinkable, even if it’s a super expansive high quality wine. That’s why is better, for young wine which can’t age in bottle long time, to use plastic closures which are TCA free.