This new type of closure was from the early 1990s as an alternative to natural cork because of the there increasingly occurring Korkschmeckers popular. The plugs are usually made of a rubber or Teflon mixture. Currently three methods are used. In the injection molding process, the plugs are cast individually, they are usually hard and very smooth and not very flexible. In the extrusion process (extruder = push out, drive) a viscous, foamed plastic mass is pressed through a nozzle in a continuous process. From this resulting strand then the plugs are cut off. In coextrusion (combining materials), a core of homogeneous, foamed plastic material is introduced into a tube made of plastic, which ensures radial elasticity. This type is considered the most suitable in terms of flexibility, tightness and uniformity.
In Switzerland, plastic corks have long been a standard and in the New world they are increasingly being used. They are available in colored versions, but also in a color that approximates the natural cork. After investigations in the viticulture institute Geisenheim is it? sulphurous acid (or sulfur dioxide) with the plastic cork reactions and is degraded relatively quickly within a few years. Studies in Australia also showed a faster pace Sulfur Removal, as well as a high oxygen permeability, which makes the wines age faster and oxidation and spoilage can lead. In the meantime, however, there are also special plastic corks with a metered oxygen management, The largest manufacturer worldwide is the company Nomacorc, See also other types of closure below closures,