Cork is an impermeable, buoyant material, a prime-subset of bark tissue that is harvested for commercial use primarily from Quercus suber (the Cork Oak), which is endemic to southwest Europe and northwest Africa. Cork is composed of suberin, a hydrophobic substance, and because of its impermeability, buoyancy, elasticity, and fire resistance, it is used in a variety of products, the most common of which is for wine stoppers. The montado landscape of Portugal produces approximately 50% of cork harvested annually worldwide, with Corticeira Amorim being the leading company in the industry. Cork was examined microscopically by Robert Hooke, which led to his discovery and naming of the cell.
Harvesting[]
Cork is extracted only from early May to late August, when the cork can be separated from the tree without causing permanent damage. When the tree reaches 25–30 years of age and about 24in (60 cm) in circumference, the cork can be removed for the first time. However, this first harvest almost always produces poor quality or "male" cork. Subsequent extractions usually occur at intervals of 9 years, though it can take up to 13 for the cork to reach an acceptable size. If the product is of high quality it is known as "gentle" cork, and, ideally, is used to make stoppers for wine and champagne bottles.
Extractors[]
The workers who specialize in removing the cork are known as extractors. Extractors use a very sharp axe to make two types of cuts on the tree: one horizontal cut around the plant, called a crown or necklace, at a height of about 2-3 times the circumference of the tree, and several vertical cuts called rulers or openings. This is the most delicate phase of the work because, even though cutting the cork requires quite a bit of strength, the extractor must not damage the underlying phellogen or the tree will die.
To free the cork from the tree, the extractor pushes the handle of the axe into the rulers. A good extractor needs to use a firm but precise touch in order to free a large amount of cork without damaging the product or tree.
Planks[]
These freed portions of the cork are called planks. The planks usually have to be carried off by hand since cork forests are rarely accessible for vehicles. Finally, the cork is stacked and traditionally left to dry, from where it can be loaded onto a truck and shipped to a processor.
Uses[]
Cork's elasticity combined with its near-impermeability makes it suitable as a material for bottle stoppers, especially for wine bottles. Cork stoppers represent about 60% of all cork based production.
Use in Wine bottles[]
Wine corks can be made of either a single piece of cork, or composed of particles, as in champagne corks; corks made of granular particles are called "technical corks". Natural cork closures are used for about 80% of the 20 billion bottles of wine produced each year. After a decline in use as wine-stoppers due to the increase in the use of cheaper synthetic alternatives, cork wine-stoppers are making a comeback and currently represent approximately 60% of wine-stoppers today.
Cork Hat[]
A cork hat (Also known as a Hobbly-Bob) is a type of headgear with cork strung from the brim, to ward off insects.
Believed by some to have been worn by jackaroos and swagmen in the blow-fly infested Australian outback, the cork hat has become part of the stereotypical, almost mythical, representation of the Australian ocker, particularly in the United Kingdom. The shape and material of cork hats vary, though typically they are shaped similar to a slouch hat. Pieces of cork, often shaped as bottle stoppers, are hung on string from the brim of the hat. The low density of cork means a number of pieces may hang from a hat without significantly increasing its weight. Movement of the head causes the corks to swing, discouraging insects from swarming around the wearer's head. In modern times the cork hat is virtually never seen and is little more than a novelty item. Further there is little evidence to indicate that its use in previous eras was any more common or widespread.
Additional Uses[]
- Cork is used in musical instruments, particularly woodwind instruments, where it is used to fasten together segments of the instrument, making the seams airtight. Conducting baton handles are also often made out of cork.
- It is also used in shoes, especially those using Goodyear Welt Construction. Cork is also used inside footwear to improve climate control and comfort.