Natural cork. From tree bark to the perfect seal.

Bark from a living tree

Cork comes from the bark of the cork oak, Quercus suber, which grows around the western Mediterranean. Portugal produces about half of the world’s cork, followed by Spain. The tree is not cut down: the bark is carefully stripped by hand and grows back.

A cork oak is first harvested when it is around 25 years old, and then roughly every nine years. The first two harvests are not good enough for wine stoppers. Only from the third harvest on, when the tree is over 40, is the bark suitable for natural corks. A single tree can be harvested for well over a century.

From bark to stopper

After harvesting, the planks of bark rest outdoors, are boiled to clean them and make them flexible, and are sorted by thickness and quality. Natural corks are punched out of the best planks in one piece. Leftover material is ground and glued into technical or agglomerated corks.

The corks are then washed, sorted again, sometimes printed or branded, and treated with a thin coating so they slide in and out of the bottle easily.

The fight against cork taint

Cork’s great enemy is TCA (2,4,6-trichloroanisole), a compound that gives wine a musty smell of wet cardboard or a damp cellar. Even tiny traces can spoil a bottle. The industry has invested heavily in cleaning and testing methods, and top producers now screen corks one by one.

For the highest quality natural corks, individual corks are even checked by trained noses, which is one of the reasons the very best corks are reserved for the very best wines.

Cork, screw cap or something else?

Natural cork lets a tiny, fairly steady amount of oxygen into the bottle, which many winemakers value for long aging. Screw caps are popular for fresh, aromatic wines and avoid cork taint. Technical corks and synthetic stoppers sit in between.

Cork forests are also valuable ecosystems that store carbon and support rare wildlife, so choosing cork can be a sustainable choice as well.