How to Tell When the Jam and Jellies are Done

How to Tell When the Jam and Jellies are Done

A thermometer is your best bet for timing the cooking of any preserve. Because temperature is affected by weather and altitude, we recommend that you test the boiling point of water each time you preserve. Adjust recipe temperatures accordingly (water boils at 212°F at sea level). Cook jellies to 8°F above the adjusted boiling point; jams and preserves need to reach 9°F above boiling.

When you’re finished processing, remove the canning rack or use tongs to remove jars. Set them on towels or rack at least 1" apart. Cool completely for 12 to 24 hours. To test the seal, press the center of each lid. If the “dip” in the lid holds, the jar is sealed. If it bounces up and down, it isn’t sealed. You may refrigerate unsealed jars and use them within 3 days; freeze them; or reprocess them in clean jars and new lids.