Cork trees - Portugal

One of the planet’s most versatile natural products, cork is a renewable raw material that has been produced in Portugal for more than 200 years.

Made from the bark of the cork oak tree, it has a unique set of advantages and is so exceptional that no man-made product has yet been able to replicate its usefulness in many aspects of industry and society as a whole.

For instance, cork is 100% recyclable, biodegradable, very light, elastic, compressible, resilient and impermeable to liquids and gases. It is also fire retardant, highly abrasion-resistant and provides a very high level of thermal and acoustic insulation.

The cork industry is as old as the art of viticulture and Portugal is a leading producer of cork with some estimations suggesting that more than half the world’s supply comes from Europe’s sun-baked south-westernmost country. Neighbouring Spain is the second-largest producer.

The country’s 70 million-plus cork oaks grow mainly in the south, most notably the Algarve, Alentejo and Ribatejo regions. The trees grow to heights of up to 10 metres (just over 30 feet) and have an average lifespan of between 150 and 200 years, yielding cork 12 to 15 times in their lifetime.

The cork can only be removed (or peeled) for the first time when the tree is at least twenty years old, sometimes more, after which it will take nine to twelve years to regrow its bark and therefore produce more cork.

Following a harvest, a number is written on the tree’s trunk, such as 25 which would indicate that the new bark won’t be ready for removal until 2034, for instance.

A very common sight for visitors travelling through southern Portugal are the bare, tangerine-coloured trunks of the many cork oaks, now a characteristic feature of the country’s landscape.

At the height of summer when the trunk has shrunk away from the gnarled, dull-grey outer skin, local workmen begin stripping the bark using special axes ground to razor sharpness, leaving the bare trunk exposed. Sap from the remaining live bark (only dead bark is removed) then turns russet in the bright sunlight, slowly darkening as time goes by.

The production of cork in Portugal

After the harvest, the cork bark is stacked, dried for at least three months (sometimes up to a year) and then taken to cork factories to be processed, first through boiling (to eliminate bugs and remove mineral salts and tannins), followed by pressing, slicing and sorting, depending on how it will be used.

Cork is perfectly suited for storing wine and winemakers the world over generally agree that no other material is more efficient for that purpose, despite the introduction of less reliable synthetic stoppers in recent years.

Many of Portugal’s most popular wines, namely port, Madeira and muscatel, not to mention a plethora of table wines, benefit greatly from cork because the bottles can be stored lying down, which keeps the cork moist and the bottle airtight.

And besides wine, wherever the cork oak grows, a local craft has been developed, such as the making of hand-produced bags, belts, key rings, boxes and dozens of other items sold at fairs and markets all over the country.

On an industrial scale, Portugal’s vast amount of high-quality cork is graded into around fifty different categories for a wide variety of uses, including floats, sound-proofing, containers for radioactive materials, beehives, insulation boards and last but not least, bottle stoppers.

Portuguese cork is also used in aircraft, for gaskets in the automobile industry, in the girders of buildings, ventilation ducts and even the air-conditioning systems of nuclear submarines.

Housed in an old cork factory, the Fábrica do Inglês (currently under development) in the ancient Moorish town of Silves (indicated on the Google map below) in the western Algarve is a good indication of the region’s importance as a cork-production centre in days gone by.

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