Why Should Pressure Canner Dial Gauges Be Tested?

Food preservation season is here! Now is the time to have pressure canner dial gauges tested to be sure they are accurate. This must be done so that low-acid foods are properly processed to prevent bacterial growth from bacteria such as Clostridium botulinum. This pathogen causes botulism which can be deadly.

Pressure canners use either a dial gauge or a weighted gauge. Weighted gauge canners do not require testing. Dial gauges can be tested using the Presto Testing Unit from National Presto Industries. Many local Extension offices have the Presto Testing Unit to test the following brands of pressure gauges:

• National
• Presto
• Maid of Honor
• Magic Seal

The USDA Complete Guide to Home Canning recommends that consumer gauges which test two or more pounds high or low of the master gauge should be replaced for safety. High readings will lead to under-processed, unsafe food. Until the gauge is replaced, adjust the recipe pressure accordingly for your elevation. For example, if the recipe calls for 11 pounds pressure and the gauge reads 1 pound high, use 12 pounds pressure.