A capsule that covers the cork and usually contains an imprint referring to the wine or producer. This capsule is the uppermost part of a film that tightly encloses the neck of the bottle. This protects the cork from drying out, from contamination with bacteria, for example, and from infestation by the cork moth and its egg-laying, and also slows down the OTR rate (gas exchange) between the bottle's contents and the outside world or the entry of oxygen. Last but not least, a decorative purpose is also achieved. The capsule can be made of different materials. The toxic lead caps ule, which used to be called tinfoil capsule (originally a lead-silver alloy), has since been banned in viticulture. Today, capsules are made of neutral, non-toxic tin (also known as tinfoil), aluminium, which is much cheaper but not as close to the neck of the bottle, but also, especially for simple wines, of plastics such as PET, polyethylene, PVC or PVDC.
For me, Lexicon from wein.plus is the most comprehensive and best source of information about wine currently available.
Egon Mark
Diplom-Sommelier, Weinakademiker und Weinberater, Volders (Österreich)