A capsule covering the cork, which usually contains an imprint indicating the wine or producer. This capsule is the upper part of a foil that tightly encloses the neck of the bottle. This protects the cork from drying out, from contamination with bacteria, for example, as well as from infestation by the cork moth and its egg-laying, and also slows down the OTR rate (gas exchange) between the contents of the bottle and the outside world or the entry of oxygen. Last but not least, this also serves a decorative purpose.
The capsule can consist of different materials. The formerly common toxic lead capsule, which was trivialized and called tinfoil capsule (originally an alloy of lead and silver), is now prohibited in viticulture. Nowadays, the capsules are made of neutral, non-toxic tin (also known as tin foil), aluminium, which is much cheaper but does not fit as tightly to the neck of the bottle, but also, especially for simple wines, of plastics such as PET, polyethylene, PVC or PVDC.
Before the cork is pulled, the foil must be cut all around with a capsule cutter (picture on the left with the four round rolling knives in the cutting sheet) and then the capsule cap must be removed (middle picture). There are also foils with a flap that can be used to expose and remove the capsule cap (arrow in the right picture). Sparkling wine bottles have a metal capsule between agraffe (wire mesh) and cork. Collecting these objects, which are sought after in the scene, is called placomusophilia. See also other alternative bottle closure forms under closures as well as under wine enjoyment.
Capsule cutter: Chiara-Kochlust
Bottles: Norbert F. J. Tischelmayer