Troubleshooting pressure canning

Asked November 10, 2015, 12:41 PM EST

After many years of successful water bath canning, I graduated to pressure canning. My first effort (beans) came out great. But the next three times, I've had major seal failures. This included chicken, veggie broth, and another batch of beans. In some cases, half the jars didn't seal (or appeared to be sealed when removed from the canner, but actually weren't). In other cases nearly all the jars were unsealed. I see evidence of venting, though I fill to the correct headroom. I have a presto canner with weighted petcock and gauge and an electric stove. The gauge was inspected this spring. The petcock makes keeping even pressure easier. I make every effort to understand and follow directions exactly and use approved recipes. I'm at a loss as to what the problem could be and any help would be appreciated.

Multnomah County Oregon home food preservation pressure canner

1 Response

Hello and thank you for submitting your question to Ask an Expert; a FREE service of Oregon State Extension Service!

I'm so sorry that your jars didn't seal! That can be such a bummer when that happens. Some common reasons why a jar might not seal are:

  • The jars were filled too high and then boiled over in the canner. Make sure jars going into the pressure canner have 1 inch to 1.25 inches of head space at the top to prevent this.
  • The rims of the jars were not wiped down before the lids were placed on. Any residue or bits of food on the rims could keep the lid from sealing.
  • Usually when folks take their jars out of the canner they are NOT sealed yet. The cooling process on your countertop is what causes a vaccum to be created and the lids to seal. If the jars were tilted to the side when you were lifting them out of the canner it can cause the liquid in the jars to push under the unsealed lid and prevent it from sealing.
  • I have also had jars that accidentally got two lids put on them before going into the canner (they stick together sometimes). That can prevent them from sealing, too.
Please note that you are ONLY able to reprocess the jars within 24 hours of them coming out of the canner. So, if you have unsealed jars you need to figure out what to do with them within that 24 hour period. Option are to:
  1. Heat and serve the unsealed jars for a meal that day.
  2. Put the unsealed jars into the refrigerator and eat within 3 days or so.
  3. Put the contents of the unsealed jars into the freezer. Most people transfer it into freezer bags but you can freeze directly in the jars too.
  4. Replace the lids and reprocess the jars in the pressure canner for the full amount of time that the canning recipe indicates.
  5. Any unsealed jars that have been left out for more than 24 hours need to have the contents disposed of.
  6. You can also find out more information on the National Center for Home Food Preservation's website at: http://nchfp.uga.edu/
If you want to go through the steps above to troubleshoot your sealing issue you can also reach me at my office at 503-397-3462. We are closed tomorrow (Wednesday) for the Veterans Day holiday. But, I will be back in on Thursday.

Take care!