At first wine was transported in sewn skins of animals and retailed, then clay jars with lid were invented, and these eventually gave way to barrels.
After the glass bottle use was popularized, corks gained prominence as closures, but unfortunately corks may taint wine with TCA (trichloranisol) and render it with very unpleasant, though not lethal. I should also mention that individuals have varying thresholds of perceiving TCA.
Ever since winemakers and scientists have been trying to find other closures. Some four to eight per cent of all corked wines are tainted, but with new treatment techniques this percentage has been decreasing gradually.
There are agglomerate corks made from ground cork; they are considered to be unsuitable as wine bottle closures. Champagne manufacturers use agglomerate cork at the top and attach thin layers of high-quality cork to the bottom where the wine comes into contact with the wine.
Then chemical laboratories and manufacturers invented the synthetic cork, which consists of plastics. They are considered to be unsuitable for high-end wines, being too tight. They are, as of now, more popular than screw caps for low to mid-priced wines.
Screw caps were originally used for inexpensive one-liter bottles of wines. For most people buying inexpensive products screw caps fit the purpose, although some slow selling wines do oxidize in the process.
Then new technologies improved the oxygen transmission rate of screw caps by adding a pad between the bottle lip and the top of the closure. This can be adjusted to specifications of winemakers. Oxygen transmission changes both the colour and taste of the wine over time.
One thing is clear – over a two-year period screw capped wines taste fresher and are more appealing than cork enclosed bottles.
New Zealand and Australia were quick to adopt the modern screw cap. They do not have cork trees and want to sell fruit-driven (fruit bombs) wines within a year or two of bottling. In new Zealand 90 percent of all wines are screw capped, and in Australia 70.
Alcan developed Stelvin, which is used in 10 per cent of bottled wines all over the world. The total world wine production is approximately 18 billion.
All screw caps are lined with Saran/tin or Saranex, of which the former allows minimal oxygen transmission. Alcan is now trying to develop a liner that will be somewhere between Saran/tin and Saranex with regard to oxygen transmission.
Then there is the Vino-lok, which is a glass stopper that seals a specially molded bottle lip with a plastic O-ring. The stopper is held in place by an aluminum cap, which must be removed manually. It looks appealing and has been quite popular in Germany and Austria. Recently northern Italian wineries started using Vino-lok.
A newer alternative metal-foil closure is Zork. It is held in place by an attractive, colourful plastic top that must be peeled of manually.
Winemakers now have a wide array of bottle enclosures from which to choose, and it seems cork with considerable research funds has maintained a good portion of market share. This is, however, tenuous and may change in the future.
Synthetic corks gained market share and will improve quality but may not dominate as Stelvin does in the non-cork segment.
Vino-lok and Zork are in contention and may still capture significant market share. With modern technology advancing rapidly, cork may be gracing only very expensive, traditional, classic wines, but we never know what the cork industry will come up with to eliminate the TCA taint.
The largest producer in the world is Portugal and exporters are bent to find a solution to the problem once and for all. Other producers are Morocco, Spain, France and Italy.
The U S A, Chile and Australia have planted cork trees with some success.

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Tags: WINE CLOSURES

This entry was posted on Wednesday, January 13th, 2010 at 06:00 and is filed under Food & Wine. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.