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Cork Myths and Curiosities

Did you know that a single cork stopper can capture up to 392g of CO2?

And that cork was used in Ancient Egypt and can be used to produce energy? Did you know that scientific research consistently proves that consumers associate cork with high-quality wines?

Find out everything you’ve always wanted to know about cork.

Stripping is the ancient process of extracting the bark of the cork oak - the cork. This work is done by specialised professionals, with absolute precision, who use just a single tool: the axe.

This delicate operation takes place between May and August, when the tree is at its most active time of growth and it is easier to remove the bark from the trunk. Harvesting cork is the world’s best paid seasonal agricultural job.

Over the course of its lifetime, a cork oak may be stripped around 17 times, at intervals of at least nine years, which means that the harvesting of the cork will last 150 years, on average.

The first stripping is called "desbóia" from which the virgin cork is obtained, which has a highly irregular structure and hardness that make it difficult to process.

Nine years later, when the second stripping takes place, the cork, known as "secundeira", has a regular structure which is not as hard.

The cork from these first two harvests is not fit for the manufacture of stoppers and thus used in other applications for insulation, flooring, decorative items, among others.

From the third and following strippings the "amadia" or reproduction cork is obtained. This cork has a regular structure, with a flat front and back and the ideal characteristics for the production of natural, quality cork stoppers.

The first stripping takes place when the cork oak is 25 years old and the trunk has reached a perimeter of 70 centimetres, measured 1.5 metres from the ground. Subsequent strippings take place at intervals of at least nine years.

No. Stripping is carried out manually and the trees do not have to be cut down. In fact, the cork oak undergoes a self-regeneration process of the bark, which gives the activity of cork harvesting a uniquely sustainable nature.

No. After stripping, the planks are stacked into piles in structures and shall remain outdoors for at least six months for the cork to stabilise. This process is governed by the strict compliance of the Code of Cork Stopper Manufacturing Practices.

A cork oak has an average lifespan of between 170 and 200 years.

Nothing is wasted from the cork oak, all its components have a useful ecological or economic purpose:

  • The acorn, which is the fruit of the cork oak, is used to propagate the species, as animal fodder and in the manufacture of cooking oils;
  • The leaves are used as fodder and a natural fertiliser;
  • The material from tree pruning and decrepit trees provides firewood and charcoal;
  • The tannins and natural acids contained within the wood from the tree are used in chemical and beauty products.

The oldest and most productive cork oak in the world is the Whistler Tree, in Águas de Moura, in the Alentejo. The cork oak was planted in 1783, stands over 14 metres tall and the perimeter of its trunk is 4.15 metres. Its name comes from the noise made by the numerous songbirds that shelter among its branches. Since 1820, it has been harvested over twenty times. Its 1991 harvest produced 1,200 kg of cork, more than most cork oaks yield in a lifetime. This single harvest produced over one hundred thousand cork stoppers.

The cork oak is an evergreen tree, of the Fagaceae family (Quercus suber), to which the chestnut and oak tree also belong. There are 465 species of Quercus, mainly found in temperate and subtropical regions of the Northern Hemisphere. Cork is harvested from the Quercus suber L species.

The cork oak may be sown, planted or propagate spontaneously, which is often the case in cork oak forests, thanks to the acorns that fall on the ground.

The cork oak is native to the Western Mediterranean Basin, where there are ideal growing conditions:

  • Sandy, chalk-free soils with low nitrogen and phosphorus, high potassium and a pH from 4.8 to 7.0;
  • Rainfall from 400-800 mm per year;
  • Temperature from -5º C to 40º C;
  • Altitude from 100-300 m.

In Ancient Greece, cork oaks were revered as the symbol of Freedom and Honour. Thus, only priests had permission to cut them down.

This is due to the high level of expertise necessary to harvest the cork without damaging this precious resource.

No. The Quercus suber L genome is the same, therefore there are no significant differences according to origin. There are, however, individual differences from tree to tree.

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