Canning, also known as "wet pack canning", is a food preservation method dating back to the French revolution. It allows one to preserve food for at least a year, although depending on the source it is said that properly home-canned food will last for decades.
The biggest reason for canning, as opposed to other food preservation methods, is that it yields ready-to-eat foods while being fairly low-tech, allowing it to be performed without any electronics or other modern equipment. Furthermore, canning is effective for preserving many types of food that others methods simply cannot preserve.
Water Bath Canning
Supplies & Equipment
Depending on the type of canning you are doing, the equipment and supplies you need will vary, but all methods require relatively simple gear.
- Jars or Cans will be required for all canning. Typically jars will be one of several brands of glass Mason jars, but many other types of glass jars can be used. You will also need lids and rings to seal the jars. Cans are also used, but typically require more equipment for processing and can only be used once. Cans do provide greater durability.
- Water Bath Canners are little more than pots with a wire-rack to protect the jars from moving around or touching the bottom of the pot. These canners can be used for high-acid foods (foods with a pH of 4.6 or lower) that don't need to be processed at the higher temperatures of foods that are lower in acidity(higher in pH).
- Pressure Canners are pots with sealable lids, pressure gauges, and pressure regulators that also have a wire rack to protect the jars. These canners can be used to can all foods as they will be able to process the food at 240F to 250F, which is required to safely can foods that are low acid foods.
Good quality, large pressure canners such as the All American can be used for both pressure canning and water bath canning. To use as a water bath canner do not attach the lid or allow it to make a seal. Leave the lid offset enough to allow for air flow.
How To Can
Canning is a relatively simple process that consists of just a few basic steps. Sterilize jars and lids with water, dishwasher or baking, prepare food to be canned (usually by boiling), pour the food into the jars and place the lids and rings on the jars, boils the jars in either a water bath or pressure canner for a certain length of time, remove the jars and allow them to cool. There are, however, more specific requirements for different types of foods and methods.
- Wash and rinse all of the jars that you will be using
- Inspect your jars for any defects and sterilize by boiling them in water, baking is not an acceptable method
- Sterilize your rings and lids in simmering water (180F), boiling could damage the seals
- Remove your jars from the water one at a time, empty the water from inside the jar, then fill with food (you will need a recipe to tell you how to properly prepare the food prior to canning as well as the appropriate amount of head space(the empty space between the lid and the top of the food).
- Remove bubbles from the food by agitating it with a non-metallic utensil, not all foods require this
- Wipe the rim clean and check it for any defects
- Place the lid and ring on the jar firmly
- Place the jar in the canner and process according to a recipe, if it water bath canner you will fill the canner to an inch above the jar lids and boil as directed by the recipe. If you are using a pressure canner there will only be 2 - 3 inches of water in the bottom of the canner and you will have to add the lid to the canner, exhaust the steam, and process for a specific time and pressure as directed by your canner's manual and your recipe.
Here are some tips and tidbits for canning.
- Add a little acid - sometimes it is better to be safe than sorry when canning and add a little acid such as lemon juice or ascorbic acid to your food to help kill off any unwanted bacteria or fungus.
- Use clean reusable lids (e.g. Tattler reusable canning lids) or new one-time use lids. Do not reuse lids intended for single use since they will not create a good seal.
- When pressure canning do not be a rush and try to remove pressure from the canner prematurely. Allow the canner to cool naturally so that the jars do not relieve themselves of pressure by letting the contents leak out of the jars.
Complications and Concerns
While canning is a relatively simple and easy process that has been performed for nearly two centuries, there are some serious health concerns to consider when canning.
- Botulism - Botulism is the biggest concern when canning. Unlike most bacteria and fungi botulism is resistant to heat, this is one reason why pressure canners are preferred as they allow a higher temperature than water bath canners.