Green Beans MUST Be Canned With a Pressure Canner
The process for canning green beans has often been controversial as many still remember old-fashioned practices learned from family and friends. Safely canning green beans requires using a tested and reliable method.
Pressure canning is the only safe method for canning green to destroy Clostridium botulinum, the bacteria that causes botulism food poisoning in low-acid foods, including green beans or other vegetables and meats. Though the bacterial cells are killed at boiling temperatures, they can form spores that can survive these temperatures. The only way to ensure that these spores are destroyed is to process foods at a temperature of 240° Fahrenheit. This temperature cannot be reached with a water bath canner and that is why it is not an acceptable method for canning green beans.
Follow this up-to-date recipe from Elizabeth L. Andress and Judy A. Harrison, So Easy to Preserve, 5th ed. This recipe has been scientifically tested and should be followed as written.
Canned Green Beans (Snap, Wax or Italian)
Select tender, crisp pods. Remove and discard diseased and rusty pods. Wash beans and trim ends. Break or cut into 1-inch pieces or leave whole.
Hot Pack—Cover beans with boiling water; boil 5 minutes. Pack hot beans into hot jars, leaving 1-inch headspace. Add ½ teaspoon salt to pints; 1 teaspoon to quarts, if desired. Fill jars to 1 inch from top with boiling hot cooking liquid. Remove air bubbles. Wipe jar rims. Adjust lids and process as directed below.
Raw Pack—pack beans tightly into hot jars, leaving 1-inch headspace. Add ½ teaspoon salt to pints; 1 teaspoon to quarts, if desired. Fill jar to 1 inch from top with boiling water. Remove air bubbles. Wipe jar rims. Adjust lids and process.
Process in a dial gauge pressure canner at 11 pounds pressure, or in a weighted gauge pressure canner at 10 pounds pressure. Process pints for 20 minutes and quarts for 25 minutes.
What about oven canning for green beans? You cannot use a conventional oven to safely process foods. The oven method involves placing jars in an oven and heating. Heat transfer in the oven is uneven, and the food does not reach high enough temperatures. Oven canning is extremely dangerous and definitely not a recommended procedure. In oven canning, product temperatures never exceed the boiling point (212° Fahrenheit) because the jars are not covered. It is, therefore, not safe to use for low-acid products such as green beans, which require temperatures of 240° Fahrenheit. The danger of inadequate processing can also pose a health risk.
The National Center for Home Food Preservation is a reliable source for current research-based recommendations for most methods of home food preservation and is accessible on the Internet at http://nchfp.uga.edu.