What does Glass stopper mean?

A glass stopper is a glass plug with a sealing ring that closes the bottle with no risk of cork taint and can be put back after opening.

Also known as: Glass cork, Glass closure

A glass stopper is a closure in the form of a glass plug pressed into the bottle neck. A thin ring of plastic or elastomer around the plug makes it seal tightly against the glass. Above the stopper there is usually an aluminium capsule that secures it until opening.

The glass stopper was developed in the early 2000s and is used mainly in Germany and Austria, though it appears in other countries too. It is most common on white and rosé wines meant to be drunk fairly young, but is also used for other styles.

Like the screw cap, a glass stopper carries no risk of cork taint, since it contains no cork. Glass is neutral and does not affect the wine's aroma or flavour. The seal is similar to a screw cap, with low and even oxygen ingress. How wines under glass develop over very long periods is less studied than for natural cork.

In practice the bottle is opened without a corkscrew: the capsule is removed and the stopper lifted out. It can then be put back. Glass stoppers cost more to make than screw caps, and the bottle needs a special neck to fit the stopper.