Seven Essential Tips to Safe Canning

Before trying any of the recipes here, you need to know how to sterilize the jars and their metal caps and rims and process the filled jars to ensure bacteria-free jams and preserves. Here’s what to do.

1. Submerge the jars and the metal caps and rims in a deep pot of cold water, preferably one with a rack to keep the jars from touching the bottom; bring to a boil and sterilize for a minute or two. Don’t put cold jars—empty or filled—into boiling water, as they may crack. Using tongs, remove the jars, caps and rims, draining the jars. Drain the pot.
2. Fill the jars while they are still hot, stopping 1/4 or 1/2 inch from the top. Wipe the glass rims, cap the jars and screw on the metal rims.
3. Fill the pot with cold water. Return the filled jars to the pot; they should be covered by two to four inches of water.
4. Bring the water to a boil. Processing time begins only once the water begins boiling, and must be increased at high altitudes. See the Web site of the National Center for Home Food Preservation (www.uga.edu/nchfp) for more information.
5. Use tongs to remove the jars, then check the seals—if liquid is dribbling out, the seal didn’t take. If you hear a hissing sound at first, don’t be alarmed—the jars may still be properly sealed. But if the hissing continues after the jar has cooled to room temperature, then start over with a new sterilized cap and rim. You will probably hear the caps make a popping sound as the jars cool.
6. Let the jars stand at room temperature for 12 to 24 hours, then check the seals by unscrewing the rims and making sure you can lift each jar by its cap. If you can also push down on the center of the lid without it popping back up, you’re good to go.
7. Discard any canned goods that smell funky, show signs of mold or are fizzing. Preserves can be stored for one year.

Published August 2003