Although jelly can be canned successfully with a warm water bath, pressure canners can also be used. Pressure canners provide higher temperatures for a longer period of time, due to the lack of air flow coming in and out of the device. Foods that are canned with a pressure canner often have longer shelf lives than those made with warm water baths or other canning methods. Pressure canners can also be used to can less acidic foods, such as vegetables, meat and fish.
Pour 2 to 3 inches of water into the bottom of the pressure canner.
Put filled jars on the rack, using a jar lifter to transfer them. Close the canner lid.
Open the vent port on the top of the pressure canner lid. Turn heat to the highest setting.
Allow steam to flow for 10 minutes, then close the vent port.
Watch the pressure gauge. When it starts to shake, set the timer for 4 minutes.
Turn off the heat and depressurize the canner for at least 30 minutes if loaded with pint-size jars, or 45 minutes if filled with quart-size jars.
Open the vent port and allow steam to escape for at least 10 minutes.
Open the lid carefully, and remove jars with the jar lifter. Allow them to cool for 12 to 24 hours.
During the 4-minute waiting period, check the pressure gauge frequently to make sure that pressure is remaining steady.
Do not force-cool the canner with cold water or ice. Exercise caution when opening the pressure canner lid (step 8). Open the lid away from your face to avoid steam burns.