Canning Basics: Annual test of dial gauge ensures accuracy.
If you have a dial gauge pressure canner, its gauge should be tested annually for accuracy (pressure canners with weighted gauges do not need to be tested for accuracy). Using a dial gauge that reads too high can result in under-processing and thus potentially unsafe food. Dial gauges that read too low can cause over-processing, which is not a safety issue but can result in lower quality, especially for fruit products.
A gauge that reads off by more than 2 pounds (high or low) should be replaced. If the accuracy is off by less than 2 pounds, adjustments can be made to ensure that the correct pressure inside the canner is achieved.
Many Cooperative Extension locations will test pressure canner gauges at no or minimal cost, or provide advice on where to send your dial gauge for testing. They offer classes on pressure canning as well, which are a great way to learn about the process whether you’re new to pressure canning or just need a refresher.
Make getting your dial gauge tested part of your annual canning equipment maintenance routine. For other pressure canner maintenance tips, see our Food Safety Bulletin, Pressure Canner Maintenance.
For further information, visit the National Center for Home Food Preservation (NCHFP) or contact your local Cooperative Extension office.
Brought to you by the UCCE Master Food Preservers of El Dorado County
Last updated July 2025