According to Wikipedia, a closure in wine parlance is “… a stopper, the object used to seal a bottle and avoid harmful contact between the wine and oxygen.”
In times long ago, this wine closure comprised wooden stoppers aided by cloth or wax.
As wine making and bottling methods became more sophisticated, cork took over as the closure of choice.
Whilst cork provides a very tight seal and is a natural product, it can allow small amounts of air into the bottle which can result in tainted wine if the bottle is unopened for a long period of time.
Of course, in many cases it is desirable to allow the wine time in the bottle to develop its full flavor and bouquet but often this can be lost due to unwelcome oxidation.
In recent times a combination of environmental concerns and cost has resulted in a reduction in use of cork as wine stoppers.
The two most popular replacement technologies are synthetic corks and screwcaps.
Synthetic corks both look like a traditional cork and will make a similar popping noise when extracted from the bottle, but suffer some negative aspects. Being made of plastic they are neither biodegradable nor recyclable so they have little appeal from an environmental perspective.
In addition, wine closures made of synthetic cork still allow air to enter the bottle prior to opening, and when a bottle is opened, they are extremely difficult to re-insert in the bottle.
The preferred modern solution to wine seals is the screwcap, also known as the Stelvin cap.
The wine screwcap is designed to both protect wine from spoiling in the bottle and yet allow ageing of the wine.
The key to the success of the Stelvin cap is that the part of the cap in contact with the wine is made of a thin coating of Teflon film over the pure tin of the cap. It is this combination of materials that allows the cap to remain stable and not impact the flavor of the wine for many years.
There is no doubting that the humble cork has built a tradition of excitement and romance surrounding the act of opening a bottle of wine. The screwcap does not match this appeal, particularly if you are dining out at a fine restaurant and enjoy the ritual of the wine waiter theatrically removing the cork from a fine bottle of wine.
However, with research showing that close to 5% of wine using cork as the closure is found to be spoiled when opened, it is easy to see why the screwcap is appearing more and more, even on highly priced premium wines.
The problem with cork is that being a tree bark, the manufacturing process requires chlorine bleach to be used to clean and brighten the final product – the wine cork. The chemical produced when the bleach and the natural molds in the cork combine is what can ultimately ruin the wine, resulting in an undrinkable wine.
There is a definite trend amongst wine makers to use screwcaps so as to eliminate the risk of tainted wine. This is a great outcome for the wine loving consumer who can be assured of a consistently high quality product.
To get an appreciation of the widespread use of the screwcap as a wine closure, visit the extensive wine shop at wine.com.