🍷 Glass stopper

A glass stopper (glass closure) is a plug of glass that fits into the neck of a bottle. It is best known under the brand name Vinolok. It contains no bark, and the seal comes from a thin plastic ring.

That ring is made of EVA, an ethylene vinyl acetate copolymer from DOW. It holds no silicone resin, PVC or phthalates, and it meets European food-contact rules. It is not glued to the glass, so you can pull it off by hand and recycle it.

The maker describes a system of three parts: stopper, bottle and capsule. The capsule, it says, protects the whole thing in storage and transport. It can be clear, PVC, aluminium or tin, or a short Alucap. The stopper is inserted by hand or by machine, from 1,000 bottles an hour by hand to more than 6,000 on a fully automatic line.

The glass comes clear, pink or black, in five collections: Classic, Duet (wood and glass), Edge, Pharma and Premium. The Classic stopper fits six neck diameters from 17.5 to 23 mm. Vinolok has been on the market for over ten years. The maker points to three studies: a 60-month comparison by the AWRI, a bottling trial at Geisenheim and a risk analysis by VLB. The page gives no oxygen figures, so you have to look in the reports themselves.

For contrast, Cork (stopper) and Agglomerated cork come from bark, Synthetic cork is plastic, and a Screw cap twists on. For what goes over the top, see Wine capsule (foil).