A special and ever more popular type of closure (English: Screw cap, twist or ROPP = Roll On Pilfer Proof Closure) of wine bottles as an alternative to cork (Natural cork) from the oak bark. These are made of non-corrosive metal (usually aluminum alloy) with an internal sealing layer polyethylene (PE), PVDC (Polyvinylidene chloride) or tin foil. In the beverage industry, this is also referred to as MCA closure (MCA = metal closure aluminum). The emotionally led discussion of whether this is associated with a "loss of culture", the relatively inexpensive production and the fact that this is the problem of Korkschmeckers can be avoided when natural corks. In addition, the often-used pro-argument for the "plop" in the Weingenuss as sensuous enjoyment not valid, because a bottle should be opened professionally as silently as possible (especially for sparkling wine).
In aircraft, for example, you have been getting only wine bottles with a screw cap for decades. Nobody finds anything here, because the advantage of simple and unproblematic opening in a narrow plane is obvious. Another advantage is that opened bottles can be closed very easily. Also optically was successful attempts to take into account the rejection of cork-friends to alternative closures. Outwardly, such screw caps are no longer recognizable as such. The first application for wine bottles took place already in the late 1970s in Australia Pioneers are the producers in the Clare Valley (South Australia). Soon followed by many producers New Zealand and California before the boom started in Europe.
Unlike a cork is in a screw cap the whitespace much bigger in the bottleneck. The volume is 15 milliliters, which means a relatively high oxygen content of 4.2 milligrams. Especially with a cold bottling air remains in the void (and thus oxygen). Therefore, when filling an air displacement means inert gas or closing under vacuum advisable. An argument often made against screw caps is that due to the much better sealing than with natural corks an oxygen supply is only possible to a small extent (factor three to four), but this is true for the bottle aging absolutely necessary. But this is more of an argument for the screw cap. Because the possibly in the bottle located oxygen in the bottleneck (but today often inert gas or vacuum) or in dissolved form in the wine itself is sufficient.
This was also impressively underlined during a 2003 Riesling tasting in Sydney Australia. A Riesling was presented to a group of leading producers from all over the world. The age was estimated between six and ten years, but in fact it was a 1982 Riesling, which was then closed with a screw cap. This suggests, at least in this case, that the maturation with such closures is slower, but the almost perfect seal through the screw cap does not cause any loss of quality. Of course, it can not be deduced from a single example if this is universally valid. However, there are many other examples that even with an absolutely tight closure, the maturation of the wine in the bottle is in no way adversely affected. This fact was also for example by several test series in the German research institute Geisenheim (Rheingau) fully confirmed.
Recent research (such as on AWRI In any case, it has been found that oxygen entering through the occlusion in minute amounts during the bottle aging very conducive to the evolution of the wine flavorings and colour can be. Especially in Australia you are indeed very positive about the screw cap. In early 2002, the Australian multi gave South Corp known that all Rieslings (including Penfolds. Rosemount Estate and Wynns ) of the vintage 2002 with screw cap instead of natural corks. From the 2004/2005 vintage, all white wines from Penfolds will be closed. This producer has also been making very successful trials with top-quality red wines since 1995. No problems could be detected, the wine matures completely evenly. In the year 2004 followed then as the first Cru-Classé-Weingut from the Bordeaux the Château Couhins-Lurton (Graves), who closes his one of the best in Graves counting white wine with a new screwdriver version.
More and more wine producers are turning to this technology. Especially in New Zealand with 90% and in Australia with 60%, the proportion of alternative closures is extremely high, with by far the highest proportion of screw cap. There were significant increases in Germany (one-third of each turn-lock, plastic and natural cork), France, which in Europe with about two-thirds of the wines with twist-lock leading Austria, Italy and Spain, as well as Argentina and Chile. A very famous brand is STELVIN which has almost become synonymous with this type of closure. The Company VinPerfect offers a screw cap that contains microscopically small holes in its cap, through which air can pass. This is the least amount of feed called nanooxigenation (see under micro-oxygenation ). See also below closures,