Testing the Seal

Remove the jars from the water bath and set to cool on a folded cloth or board. Let them stand for 24 hours before testing the seal. The lids of screw-top jars should pull down and make a seal as they cool; the lid will appear slightly concave. If the lid remains flat, press it with a finger—if it pops up, the jar is not sealed. Alternatively unscrew the lid and remove the screw band. Lift the jar by the lid. If you can do this, a vacuum has formed and the seal is secure. To test clamp-on jars, tilt the jar to press the food against the lid; bubbles indicate a poor seal. If the jar is not correctly sealed, reprocess it immediately or refrigerate the food and consume it within a few days. Wash correctly sealed jars, label them and store in a cool, dark place for up to a year. Wash and store the screw rings separately for future use. Repeat the seal test before consuming the contents of the jars.