Once your jars of home canned food have cooled overnight (12-24 hours) after being processed in the canner, check they have sealed before labelling and storing in a cool, dark and dry place. Here are several indicators of a good vacuum seal. If jars have not sealed, they need to be reprocessed within 24 hours, or you can refrigerate/freeze the jar contents instead - use wide mouth jars if freezing.Ball Mason jars, Mad Millie jars, Better Homes & Gardens jars and other jars with two-piece lids
Cool jars overnight, do not adjust lids and do not tighten bands during this time. The next day, remove the screw band. Press the middle of the lid, a good seal WILL NOT flex up or down. Looking at eye level, the lid should be concave (curved downwards in the middle) slightly, showing a good vacuum seal is present. If lids are bulging (curving upwards) or lids are loose (slide off), the jars have not sealed. Store sealed jars without the screw bands in a single layer on the shelf.
Bormioli Riocco jars and other jars with one-piece (twist top) lids
Cool jars overnight, do not adjust lids and do not tighten lids during this time. The next day, press the middle of the lid, a good seal WILL NOT flex up or down. Looking at eye level, the lid should be concave (curved downwards in the middle) slightly, showing a good vacuum seal is present. If lids are bulging (curving upwards) or lids are loose (slide off), the jars have not sealed. Label sealed jars then store in a single layer on the shelf.
Fowlers Vacola, and other jars with three-piece lids (or with clips)
Cool jars overnight, do not adjust lids or clips during this time. The next day, remove clips and press the middle of the lid, a good seal WILL NOT flex up or down. Looking at eye level, the lid should be concave (curved downwards in the middle) showing a good vacuum seal is present. If lids are bulging (curving upwards), the jars have not sealed. Lids should not be loose and should not wiggle. Store sealed jars without the clips in a single layer on the shelf.
Other types of jars
Refer to the instructions by the manufacturer.