Canning, or as some in the Appalachian Mountains say, putting up, is a way of preserving food safely for long periods of time. This is either by pressure canning or boiling-water bath canning.
How do you decide which method to use? Let's look first at the food. Foods are classified as either low or high acid foods. The acid level is based on the pH of the food. For a food to be a high-acid, its pH must be 4.6 or less. If the pH is higher, then the food has very little natural acid and is referred to as a low-acid food.
High acid foods include all fruits, tomatoes, and pickled vegetables. The boiling-water or water bath canning method is used for these foods. A large pot will work or you can purchase a water bath canner. If you are going to use a large pot you have on hand make sure that the pot is deep enough to have at least 2 inches of water over the top of the jars and 2 inches extra space for boiling. You should also be able to fit at least 5 jars in it with none of them touching. In order to prevent losing the water in the canner up to steam, it must have a snug-fitting cover. You also need a metal rack to keep the jars from touching the bottom of the pot. You can process two layers or decks at a time. If you plan on double decking your jars you will need to place a second rack between the layers of jars.
Low-acid foods include all vegetables (except tomatoes as mentioned above), meats, poultry and fish and must be processed in a pressure canner. The reason being is that these foods require processing above 240 degrees F in order to assure that there are no toxins or bacteria, such as Clostridium botulinum (botulism), remaining and only a pressure canner and achieve these temperatures.
For pressure canning, you really need to have a canner especially made for that purpose. It must contain a rack to keep the jars off the bottom of the pot. Pressure canners have gauges that maintain the pressure inside the pot. There are two types of gauges. One, the weighted gauge will have three markings, one for 5 pounds, 10 pounds or 15 pounds of pressure. Different foods require different pounds of pressure to be process under. The other type of gauge is the dial gauge. People living in higher altitude areas will need this type of gauge. Higher altitudes require the pressure needed by usually 1/2 pound per 1,000 feet above sea level. The recipe for each food will have this information.
Whatever you are going to can, it is important to follow the recommended temperature, pressure and cooking time for each recipe.
Remember, use the appropriate method for the foods you will be canning. For high-acid foods, use the water-bath canner and for low-acid foods always use the pressure canner method. Happy canning.
Betty Powers is passionate about canning. She currently runs a web site where you can purchase quality canners of all types. Go to pressurecannersusa for free recipes and home canning information and tips.