Canning extends the life of foods by stopping the natural process of deterioration in food caused by micro-organisms. This is done through boiling and sealing. Despite its name, canning doesn’t involve cans at all but preserves food in tightly sealed glass jars. While food preservation can be simple, canning is a method that typically requires more resources and attention. Canning gone wrong can have serious food safety implications.
Home canning in its simplest form is the water-bath method. This method is suitable for high acidity foods. Jars are stuffed with acidic produce such as tomatoes, berries or cucumbers in vinegar, and closed with a lid. They are then immersed and boiled in an open bath of water. This process causes a seal to form under the lid, forcing out air and creating an acidic environment in which bacteria cannot flourish.
This Youtube video depicts the water-bath process of canning.
Pressure canning is a more advanced means of canning food. It requires a greater level of skill and specialised equipment. Pressure canning is the only safe canning method to preserve poultry, meat, fish, dairy, and certain vegetables. Low acidity foods do not contain enough acid to inhibit the growth of toxic Clostridium Botulism spores and thus require a pressure cooker to reach a temperature high enough to kill these micro-organisms. Canned goods should be stored in a cool dark dry place.
This Youtube video shows the process of pressure canning.