Cooling Jars & Checking Jar Seals

Once your jars of home canned food have cooled overnight (12-24 hours) on a towel, 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, the contents need to be refrigerated or frozen.
   
Ball Mason jars
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 curved downwards, showing a good vacuum seal is present. If lids are bulging (curving upwards) or lids are loose (slide off) after removing the bands, jars have not sealed. Store sealed jars without the screw bands in a single layer on the shelf.
   
Fowlers Vacola Jars
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.