Boiling Water Bath Canning Method
A boiling water canner is a large kettle with a lid and internal rack. It must be deep enough to allow jars to be covered with 1 to 2 inches of water and still have additional height for water to boil actively. The jars must be held off the bottom so the heat can penetrate properly. The jars are divided so they will not bump into each other or tip over in the boiling water. The jars should be covered by one (to two) inches of water when it is briskly boiling, so the heat thoroughly penetrates the food at the top of the jar. An additional one to two inches of air space should be allowed between the top of the boiling water and the top of the kettle (pot).
The boiling water bath canning method is recommended for canning high acid foods such as: fruits, tomatoes, (when an additional acid has been added) pickles, relishes, and other foods with vinegar added. This method is adequate to destroy molds, yeasts, enzymes, and some bacteria.
For complete step-by-step instructions, see links below.