Cork (material)

Image:Cork stopper.jpg
A cork stopper for a wine bottle

Cork material is a subset of generic cork tissue, harvested for commercial use primarily from the Cork Oak tree, Quercus suber, with Portugal producing most cork worldwide.

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. Cork's low density makes it a suitable material for fishing floats and buoys. Sheets of cork, often the byproduct of more lucrative stopper production, are used to make floor tiles and bulletin boards.

The cork industry is generally regarded as environmentally friendly. The sustainability of its production and the easy recycling of cork's products and by-products are two of its most distinctive aspects.

Cork demand has increased due to a larger proportion of wine being sealed with cork rather than being sold in bulk. Since a tree's bark can only be harvested once a decade or so, supply is highly inelastic. Top quality corks are quite expensive, so cheaper brands have switched to lower quality cork, synthetic plastic stoppers, screwcaps, or other closures. These also eliminate cork taint. The synthetic stoppers also do not dry out and shrink so the bottles do not have to be on their sides to prevent the wine from oxidizing. However, on the down side, both synthetic stoppers and screwcaps require different winemaking methods to some extent, as sulfur dioxide (SO2) levels need to be different, and there may be different wine faults due to oxidation or reduction.

Cork contamination with harmless but foul-smelling trichloroanisole (TCA) is one of the primary causes of cork taint in wine. Cork related trichloroanisole has been reduced by means of new and more reliable production methods, such as changes in the bleaching process.

Recently cork has also been used in rocket technology due to its fire resistance. It can also be used as bricks for the outer wall of a house (this was done in Portugal's pavilion at Expo 2000).

Note that the Cork Oak is unrelated to the "cork trees" (Phellodendron), which have corky bark but are not used for cork production.

See also

  • APCOR, Portuguese Cork Association

External link

eo:Korko fr:Liège (matériau) gl:Cortiza he:שעם ms:Gabus nl:Kurk ja:コルク pt:Cortiça sv:Kork wa:Lidje (schoice)