What does Closure mean?

The closure is what seals the bottle, such as natural cork, screw cap or glass stopper, and it affects how the wine develops in the bottle.

Also known as: Stopper, Bottle seal

The closure is what seals the wine bottle. The most common types are natural cork, technical cork made from pressed cork granules, synthetic cork, screw cap and glass stopper. Sparkling wine uses a special mushroom-shaped cork held in place by a wire cage.

The choice mainly controls how much oxygen reaches the wine after bottling. Natural cork lets in very small and somewhat variable amounts of oxygen, which has long been seen as helpful for wines meant to age. Screw caps and glass stoppers seal more evenly, and with a screw cap the liner under the cap decides how much oxygen gets through.

The closure also affects the risk of cork taint. The compound TCA can occasionally occur in natural cork and gives a dull, musty smell of damp cellar. Screw caps and glass stoppers carry no such risk, but a very tight seal can instead bring out reductive notes in some wines.

Closure is no reliable sign of quality. The choice often reflects tradition, region and the producer's view of how the wine should develop. That is why it is shown on the wine page, so you know what to expect when the bottle is opened.