Canning under pressure

EXTENSION UPDATE

By Katherine Allen

County Extension Director

UF/IFAS Suwannee County

Extension Director

Nothing is more satisfying than watching seeds planted in a garden which grows into vegetables to be eaten. But, you may have more than you (and your neighbors!) can eat during the season. Canning can help you store the food for when the garden is no longer producing.

Spoilage occurs when microorganisms, such as bacteria, fungus, viruses or parasites, are allowed to grow on food. Canning makes the food safe, but only if it is done properly. Foods are placed in jars and heated to temperatures that destroy microorganisms and also slow the enzymatic process (which chemically matures the fruits and vegetables). When the jars cool, a vacuum is created which prevents additional contamination from entering the jars. Low acid foods like vegetables and meats must be canned in a pressure canner at 240° F. at 10 lbs. of pressure, while acid foods such as fruits and jams or jellies can be processed in a boiling water bath.

Because of the danger of Clostridium botulinum (which causes the food poisoning botulism), the low acid green beans are a food that must be pressure canned to be safe. The spores of Clostridium botulinum can be destroyed by canning the food at a temperature of 240° F. or above for a specified period of time. This temperature can only be achieved in a pressure canner since it is a temperature above boiling water (212° F.). It is important to obtain recent, research-based recipes since old time tables for processing foods used only a water bath canner, which research has now found to present a very serious risk of botulism. University of Georgia has an excellent Web site at http://www.uga.edu/nchfp/ or contact your local Extension office for updated information.

It takes about 1 1/2 to two pounds of green or wax beans to make one quart jar of canned beans. So, for a 30 lb. box, you will need about 15-20 quart jars.

In addition, the beans may be packed into the jars raw or they may be preheated first before packing. Raw pack means that the raw, unheated food is placed directly into the jars and then boiling water is poured over the beans. The beans must be packed tightly as they will shrink during processing. Hot pack means heating the food to boiling and then placing the hot food and liquid into the jars. Hot packed foods should be placed in jars loosely as shrinkage has already taken place.

Commercially prepared canned goods typically contain a lot of sodium. The good news? During canning, salt is not needed for preservation, but simply for taste and/or color protection. Therefore, if you have someone who is watching their salt intake, and the recipe calls for a teaspoon or two of salt, it can be eliminated. NOTE: Salt is used for its preservative effect during fermentation for pickling, for example. If the recipe calls for a large quantity of salt, it cannot be eliminated or substituted.

If you are growing your own food and paying for fertilizer, pesticides, water and equipment, the canned food may not be saving you money. However, gardening and spending time with loved ones putting away foods in a time-honored tradition to leave freezer space for other products can be very rewarding.

If you need more information on food preservation or gardening, contact the UF/IFAS Suwannee County Extension office at 386/362-2771 or stop by 1302 11th St. SW in Live Oak, next to the Coliseum.

All programs and related activities sponsored for, or assisted by, the Institute of Food and Agricultural Sciences are open to all persons with non-discrimination with respect to race, creed, color, religion, age, disability, sex, or sexual orientation, marital status, national origin, political opinions, or affiliations.

For persons with disabilities requiring special accommodations, please contact our office at least five working days prior to the program so that proper consideration may be given to the request. Our phone number is 386-362-2771. For the hearing impaired, please contact the Florida Relay Service at 1-800-955-8771.

Canning snap, wax, or Italian green beans

Select tender, crisp pods. Remove and discard any 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 in pan and boil 5 minutes. Pack hot beans into hot jars, leaving 1-inch headspace. Add 1/2 teaspoon salt (optional) to pints; 1 teaspoon to quarts. Fill jar 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 1/2 teaspoon salt to pints; 1 teaspoon to quarts, if desired. Fill jars 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 of pressure or in a weighted gauge pressure canner at 10 pounds of pressure:

Pints..............20 minutes

Quarts............25 minutes