How to Process Jam Jars 1. Using a clean spoon, fill the sterilized jars with hot jam, taking the required headspace into account. 2. Stir with a clean small spatula to eliminate any air pockets, then wipe the rims clean with a damp paper towel. (Any residual stickiness or seeds will affect the seal.) 3. Place sterilized lids on the jars. Screw on the sterilized bands until snug. Place a rack in the bottom of a pot, then fill halfway with water, cover and bring to a gentle boil. 4. Using a jar lifter, lower the sealed jars into the pot. The water must cover the jars by 1 inch (add boiling water, if needed). Cover the pot and process for 15 minutes. 5. Turn off the heat and uncover the pot; let the jars sit in the water for 5 minutes, then remove to a kitchen towel with a jar lifter. Let cool at room temperature, 12 to 24 hours. 6. Check the seal: The lids should be flat. Sealed jars can be stored in a cool, dark place for a year. (Refrigerate after opening.) If they've popped, you can keep the jam in the fridge for up to 1 week.