Canning season is almost here. When canning low acid foods like meat, poultry, fish, and vegetables, be sure to use a pressure canner. Pressure canning can kill the spores of the deadly bacteria, Clostridium botulinum. However, just using a pressure canner does not guarantee safe food. You must follow specific guidelines to ensure safe food. Here are essential 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 at least once a year and if it is significantly bumped or dropped. University of Idaho Extension in Franklin County tests dial gauges at no charge. The process only takes a few minutes. Weighted gauges don’t need to be checked.
2. Adjust pressure for altitude. At sea level, water boils at 212 degrees Fahrenheit. 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 before processing. 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 petcock. 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. Up-to-date, research-based recommendations can be found at the University of Idaho Extension Publication website https://tinyurl.com/uidaho-food-preservation, National Center for Home Food Preservation website http://nchfp.uga.edu/, and Ball website http://www.freshpreserving.com/.
5. Pay attention. Pressure canning requires you to be physically there and paying attention to ensure that the pressure stays where it needs to be. If it drops below the correct pressure, you will need to turn up the heat, bring it back up to the required pressure, and start the timing over again from the beginning. If the pressure goes too high, it could potentially damage the jars or canner.
For more information, contact University of Idaho Extension, Franklin County at (208) 852-1097 or firstname.lastname@example.org.