Canning is a preservation method, where foods are packed in glass jars and immersed in either a waterbath or pressure canner and heated for a specific amount of time at a certain temperature. The type of food will dictate what type of canner must be used, temperature maintained and the process period that is required.

Processing foods such as fish or meats in metal tins is also a form of home canning, but it requires specialized equipment to apply and seal the metal lids to canning tins. It is more difficult to obtain information or supplies and equipment sources for this type of canning and it is therefore not as popular as canning with jars.

Maintaining heat and pressure during the canning process prevents harmful organism and bacterias from causing food spoilage and health concerns. When the canning time period has expired and it is safe to remove jars, during the cooling-off period, a vacuum is formed causing air to escape from the jars to form a safe airtight sealing of jar contents. This further protects the canned foods from bacterial growth, deterioration and spoilage.