It’s that time of year to think about canning. While most people feel comfortable using a boiling water canner, some people are frightened by using a pressure canner. The USDA recommends using a pressure canner when canning low acid foods like meat, poultry, fish and vegetables, or mixtures of food containing these foods. Pressure canning can kill the deadly bacteria, Clostridium botulinum that love to grow in moist, low-acid, home canned foods. However, just using a pressure canner does not guarantee safe food. You must follow specific guidelines to ensure safe food. Here are four critical steps in pressure canning.
1. Get your dial gauge tested every year before using. Dial gauges are sensitive and can easily become off from a bump or drop. If this happens, it is important to have the gauge tested. University of Idaho Extension, Franklin County tests dial pressure canner gauges. It only takes a few minutes and it’s free.
2. Adjust pressure for altitude. At sea level, water boils at 212 degrees. This is the highest temperature that food/liquid will reach in a normal cooking environment. A higher temperature is needed to destroy botulism spores. A pressure canner is needed to reach that temperature. The pressure needed at sea level is 10 pounds. As altitude increases, atmospheric pressure decreases. Greater pressure must be used at higher altitudes to reach the same temperature it did at sea level. Increase pressure by one pound for each 2000 feet above sea level. Franklin County is between 4001-6000 feet above sea level. Use 13 pounds pressure or higher with a dial gauge or 15 pounds pressure with a weighted gauge.
3. Vent pressure canners for at least 10 minutes. When you close the lid on your pressure canner, air is trapped inside. This trapped air lowers the temperature of the pressure canner and results in under processing. To vent a canner, leave the vent port uncovered or manually open petcocks. Heat the canner with lid locked into place until water boils and generates steam. When steam flows freely from the open petcock or vent port, set a timer for 10 minutes. After venting for 10 minutes, close the petcock or place the weight over the vent port to start pressurizing the canner.
4. Use current recommendations and recipes. It is not recommended to make up your own recipes because they may not be safe to can. Many factors affect whether a food is canned safely include processing time, acidity, food thickness, size/shape of jar, etc. Lots of research and testing go into deciding what recipes and processing times are safe to can. Additionally, the ways that people may have canned food in the past may not keep food safe today. Microorganisms (bacteria, viruses, fungi) have to adapt to survive. Therefore, what worked in the past may not work today. Because of these issues, completely follow current research-based recipes and recommendations. Current, reliable, research-based recommendations can be found at the National Center for Home Food Preservation website http://nchfp.uga.edu/, the Ball website http://www.freshpreserving.com/ or at University of Idaho Extension, Franklin County.
For more information, contact University of Idaho Extension, Franklin County at (208) 852-1097 or firstname.lastname@example.org.