By Shirley Camp, retired University of Illinois Extension Educator
Canning season is in full swing. Sweet corn, green beans, lima beans, tomatoes, peppers, and a whole host of other foods are ripe for the picking. I hope you have your pressure canner ready to go – if yours is a dial gauge type canner, the gauge needs to be tested annually. Many local Extension Offices have testers and can do this for you (sometimes there is a nominal fee).
Prep Tip: Check the seals while you are getting it ready. If your pressure canner has any gaskets or seals that are dried out or cracked, replace them. This will help your canner hold pressure while you are processing the foods. Also, the pressure saucepans are not meant to be canners and all recommendations are that you not use them as such.
Pressure Canning Know-How Tips: You should have a manual or canning book that describes the pressure canning process. Briefly, place 2 inches of water in the bottom of the canner with the rack in place. Place the canner on the range top on a burner that closely matches the size of the canner and heat the water. Once you have filled the jars, added the lids and rings, place the jars on the canning rack. Put the lid on the canner, closing it securely but making sure that the vent is open. When a plume of steam is coming from the vent, set the timer for 10 minutes and let the canner exhaust through the vent for that period of time. After 10 minutes, close the vent (usually with a weight in a weighted-gauge canner or the vent cover in a dial gauge type). The pressure will build – watch it carefully – until the pressure is at about 8 pounds. (In a weighted gauge canner the steam will begin coming out the gauge or the gauge will move and make a noise.) Adjust the heat down until the pressure reaches 11 pounds or the weighted gauge “rocks” as described by the manufacturer.
Start the timing process once the desired pressure is reached. Adjust the heat under the canner is needed to maintain the pressure slightly above the correct temperature. Loss of pressure means you will have to start the process over so careful attention is needed during this period. When the canning process is completed, turnoff the heat and remove the canner from the burner, if possible. During the cooling process, the canner is depressurizing; this should be allowed to occur without force cooling the canner with cold water or other methods. It may take as long to depressurize as it does to pressure can the food. When all pressure is out of the canner, remove the weight from the vent or open the petcock. Let the canner sit unopened for 10 minutes then lift the lid with the underside away from you to avoid burning yourself. Using a jar lifter, remove the jars to a rack or folded towel to cool for 24 hours. Test for seals. Label and store.
Safety Tips: Do not leave the jars of food in the canner overnight.
If you live at a higher altitude, charts for adjusting the pressure are available in canning books or from your local Extension Office.
Remember, the only SAFE way to process low-acid foods (which are all vegetables, meats, and vegetable mixtures) is by using a pressure canner. This is because of c. botulinum toxin, which is present in low acid foods. C. Botulinum is only destroyed at temperatures above 212°F. which can only be achieved in a pressure canner. Now I know some of you will say your oven reaches temperatures higher than this BUT the oven does not remove air from the jars, which is necessary to prevent botulism toxin from growing. Pressure does this.
Any way you look at it, you cannot safely can corn, green beans, or any other vegetable without a pressure canner. Period. Other methods are very risky and can result in botulism poisoning which attacks the central nervous system and can cause death. Any questions?
Green Bean Tip: Adding ingredients like ham/bacon to green beans is not safe either. Can the green beans adding only Mrs. Wages Canning salt if you add anything. Green beans may be packed either raw or hot. Either way, pack the beans tightly into the jars and add salt as desired. Fill the jar to within 1-inch with boiling water and remove air bubbles. Wipe off the jar rims and process at 11 pounds in a dial gauge canner or 10 pounds in a weighted gauge canner 20 minutes for pints and 25 minutes for quarts.