Canning interrupts the natural decaying process by heating the food in a container. The heat destroys potentially dangerous microorganisms, including molds, yeasts, enzymes and bacteria. All foods are either high acid or low acid.
High-acid foods include all fruits, pickles and tomatoes or foods that have had lemon juice, citric acid or vinegar added to them. Foods in this category have a pH of 4.6 or lower. The boiling-water canning method of processing is sufficient for high-acid foods. All the recipes in this article use the refrigerator technique or the boiling-water canning method.
Low-acid foods include vegetables such as okra, carrots, beets and green beans. It is necessary to process these vegetables at 240 degrees in a pressure canner. (This, frankly, is what seems like the scary stuff.) The difference is that around 212 degrees, the boiling point of water, is the temperature at which molds, yeasts and some bacteria are destroyed in high-acid food. However, in low-acid food, the temperature necessary to destroy bacterial spores is 240 degrees, much higher than the temperature of boiling water. So, a steam-pressure canner is necessary to achieve that temperature.
Refrigerator technique
An alternative technique is the refrigerator method.
Best used with small batches of jams, jellies and pickles, the refrigerator method relies on short-term storage in the refrigerator or freezer to impede mold and bacterial growth.
To preserve by the refrigerator method: Place the jars in a large stockpot and cover with water by an inch to submerge. Bring the water to a gentle boil and simmer for 10 minutes. Keep them in hot water until ready to fill. Place the lids in a saucepan and add water to cover. Bring the water to a simmer, about 180 degrees without boiling.
Boiling-water canning
If you want to make shelf-stable products that do not need to be kept in the refrigerator, you need a home canning kit for boiling-water canning.
This kit includes everything you’ll need: a boiling-water canner, rack, lid and canning tongs to safely lower and remove the jars. Many contain starter jars, tempered glass jars with a two-piece cap with a flat, rubber-lined metal lid and a metal screw band. The jars and lids must be sterilized before filling. Place the lids in a saucepan and add water to cover. Bring the water to a simmer, about 180 degrees without boiling.
To sterilize the jars before filling, place them in a large stockpot or in the rack in the canner kettle and cover with water.
The jars must be totally submerged. Bring the water to a boil. Boil the jars for 10 minutes for altitudes at or below 1,000 feet above sea level. At higher elevations, boil 1 additional minute for each 1,000-foot increase in elevation. Allow the jars to remain in the hot water until ready to fill, and seal with the sterilized two-piece lids.
Once the jars are filled and sealed, submerge them in the boiling water canner, making sure they are covered by at least 1 inch. It is necessary to set a timer after the water is boiling for processing. The length of time the jars have to be processed depends on the size of the jar and the level of acidity of the product.
What is pectin?
Jellies and jams are fruit products that are jellied or thickened, and mostly preserved by sugar. A successful gel of both depends on the proper ratio of fruit, pectin, acid and sugar.
Pectin is the substance that causes the fruit to gel. Some kinds of fruits, including apples and berries, have enough natural pectin to make high-quality products. The highest-quality pectin is found in ripe fruit. Pectin from under-ripe or over-ripe fruit will not gel.
For more canning information: See the Ball canning company website: .
