Proper storage of home canned foods

Tips for checking your jar seals and storing home canned goods safely.

Now that canning season is in full swing, Michigan State University Extension would like to bring awareness to how to properly store your home canned products. Your first step after processing is to check if your two-piece lid has sealed. MSU Extension recommends using the flat lid and ring band.

There are three ways of testing your jar seals after cooling for 12 to 24 hours:

  1. Press the middle of the lid down, if it springs up, the lid is unsealed
  2. Tap lid with the bottom of a teaspoon. A dull sound means food is in contact with the underside of the lid and it is not sealed. If the jar is sealed it will make a ringing, high-pitched sound.
  3. The lid should be curved down in the center, if it is either flat or bulging, it may not be sealed.

Good news! You can reprocess your unsealed jars within 24 hours. Remove the lid, check jars for small nicks or cracks and if necessary, change jars, add a new lid. The same screw bands can be used and reprocess using the same processing time. You also have the option to allow for headspace in the jar and freeze the food or refrigerate and eat it within 2 to 3 days. 

For the jars that are cooled and tightly vacuum-sealed, it is recommended by the National Center for Home Food Preservation that the jars be stored without the ring bands (allows for easier detection of broken vacuum seals) and the outside of the jars be washed and rinsed of food residue. Label and date each jar and store in a clean, cool, dark, dry place. For best quality, store between 50 and 70 degrees Fahrenheit and can only the amount of food you will use within a year. It is not recommended to store jars above 95 degrees F, these damp conditions may corrode metal lids, break seals and allow for recontamination and spoilage. 

If jars are to be stacked for storage, be careful not to disturb the vacuum seal. It is recommended to stack jars no more than two layers high with a supporting barrier in-between layers as a preventative against disturbing the seals on the lower jars. 

If unsealed jars or food show signs of spoilage, do not taste! Examine each stored jar before using, look for vacuum, concaved lids, streaks of dried food on outside of jars, air bubbles and unnatural color in the food. 

Remember “If in Doubt, Throw it Out!”

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