Family and Consumer Sciences Education: 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, we would like to bring awareness to the proper storage of home canned products. Your first step after processing is to check if your two-piece lid has sealed.

   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 the lid with the bottom of a teaspoon. A dull sound means food is in contact with underside of lid and therefore, 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.

   If your jar is unsealed, you have 24 hours to reprocess it. Remove the lid, check the jars for small nicks or cracks, wash and rinse jar, add heated product into the hot jar, add a new lid with the same screw band and reprocess using the same processing time. You also have the option to refrigerate and eat it within two to three days. 

   The National Center for Home Food Preservation recommends removing the ring bands before storing. This allows for easier detection of broken vacuum seals. Label and date each jar and store in a clean, cool, dark, dry place. For best quality, store between 50- and 70-degrees Fahrenheit (F) 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 each layer as a preventative against disturbing the seals on the lower jars. 

   If jars become unsealed or food show signs of spoilage, do not taste it!  Examine each stored jar before using it. Look for vacuum, concaved lids, streaks of dried food on outside of jars, air bubbles and unnatural color in the food to determine if it is safe to eat. Remember, if in doubt, throw it out!

Source: Michigan State University Extension