Alternative wine closure

The emergence of these alternatives has grown in response to quality control efforts by winemakers to protect against "cork taint" caused by the presence of the chemical trichloroanisole (TCA).

[1][2] The closures debate, chiefly between supporters of screw caps and natural corks, has increased the awareness of post-bottling wine chemistry, and the concept of winemaking has grown to continue after the bottling process, because closures with different oxygen transmission rates may lead to wines that taste different when they reach consumers.

[6] "Extensive quality tests show convincing results: apart from protecting against cork taint, screwcaps are also beneficial in the aging of wine, particularly preserving the aromatic freshness.

"[10] An often cited contradiction is the case of experiments carried out by Château Haut-Brion in the 1970s, when 100 bottles were placed under screwcap for long term observation.

The result was, according to Haut-Brion manager Jean-Bernard Delmas, that "it worked perfectly for the first ten years, until the plastic in the caps went brittle and let air in".

[13] The 2007 Victor Segalen University study in Bordeaux showed that screw caps closures allowed the lowest amount of oxygen permeation when compared to natural and synthetic corks, offering the highest level of protection against oxidation of the wine.

Using a glass stopper with an inert o-ring, the closure is claimed to create a hermetic seal that prevents oxidation and TCA contamination.

In March 2006, the Spanish government outlawed the use of alternative wine closures in 11 of Spain's wine-producing regions as part of their (Denominación de Origen) D.O.