Plastic Safety Cork / Bung For Glass Demijohn

An easy way to store wine safely in a one gallon glass demijohn after fermentation has finished - fitted instead of a solid bung

If any secondary fermentation or expansion takes place, this release valve bung will let gas escape safely whilst still protecting the wine from airborne contamination.

Fits most  glass demijohns which are compatible with 1 gallon cork or rubber bungs