Extension > Food > Food Safety > Preserving and preparing > Canning > Boiling water bath canning
Boiling water bath canning
When buying a boiling water bath canner it is important that the canner be deep enough so that at least 1 inch of briskly boiling water will be over the tops of the jars during processing. If you have an electric range you must use a flat bottomed water bath canner to get the best transfer of heat. Either a flat or a ridged bottom boiling water bath canner can be used on a gas burner. To ensure uniform processing of all jars with an electric range, the canner should be no more than four inches wider in diameter than the element on which it is heated. However for flat top stoves, canners should be flat and 2 inches wider than the diameter of the element. These are the basic steps for successful boiling water bath canning:
- Fill the canner halfway with water.
- Preheat water to 140 degrees F for raw-packed foods (the lower temperature reduces jar breakage) and to 180 degrees F for hot-packed foods.
- Load filled jars, fitted with lids and rings, onto the canner rack and use the handles to lower the rack into the water, or fill the canner, one jar at a time, with a jar lifter.
- Add more boiling water, if needed, so the water level is at least one inch above the jar tops.
- Turn heat to its highest position until the water boils vigorously, set a timer for the minutes required for processing the food.
- Cover the canner and lower the heat setting to maintain a gentle boil throughout the processing time.
- Add more boiling water, if needed, to keep the water level at least one inch above the jars.
- When the jars have been boiled for the recommended time, turn off the heat and remove the canner lid.
- Use a jar lifter to remove the jars and place them on a towel, leaving at least one inch between the jars during cooling. Do not retighten the jar lids because you will break the seal. Do not leave the jars in the boiling water after processing time is done because the food will spoil.
- Check the jar seals 12-24 hours after processing. To store, remove the screw bands and wipe the jars clean. Any jar that fails to seal can be reprocessed in a clean jar with a new lid. Reprocess within 24 hours. Or the jar may be refrigerated and used within several days. The jar may also be stored in the freezer if the headspace is adjusted to 1-1/2 inches to allow for the expansion of the product.
