A device made of glass or plastic and designed to prevent wine contamination and to release carbon dioxide gas during FERMENTATION. The air lock fits into the top of the vessel containing the fermenting wine and is filled about halfway with water. As the carbon dioxide gas builds up during fermentation, it forces its way through the water barrier and out of the container. Outside air doesn’t have enough pressure to force its way into the air lock so the wine is protected from outside contaminates.