Tool: Water Bath Canner
A water bath canner is a large cooking pot, similar to a stock pot, with a tight fitting lid and a removable wire or wooden rack that keeps the jars separated from each other, preventing cracking or breakage. The rack allows the boiling water to flow around and underneath jars for more even processing.
If no rack is available, clean dish towels (preferably dye-free cotton) can be used to pack around jars. If a canner is not available any large cooking pot may be used provided it is deep enough for l to 2 inches of briskly boiling water to cover the jars. The diameter of the canner should be no more than 4 inches wider than the diameter of a stove's burner to ensure proper heating of all jars. For an electric ranges, the canner must have a flat bottom.