Home canning is a way to preserve food. The process starts with disinfecting the glass jars. The pots or bottles are filled with the foods to be preserved. The jars are closed with a glass lid. Between the jar and the lid comes a rubber ring: the canning ring. To keep the lid in place, it is shut with a metal clasp. The jars are put in a canning kettle with nearly boiling water for a while. This makes the air escape from the jar, creating a vacuum inside. The clasp prevents the lid to blow off. When the jar has cooled, the clasps can be lifted. The content of the jar is now storable for years. The jar can be opened by pulling the tongue of the canning ring. The jars can be reused for canning food after thorough cleaning.