Always follow these basic rules to ensure food safety and success.
Know Which Canner To Use: The boiling-water canner—basically a big pot with a lid and a rack in the bottom—is used for high-acid foods, which naturally resist bacteria growth. Pressure canners are used with low-acid foods and recipes that are especially prone to harboring harmful microorganisms. They heat food hotter than boiling-water canners.
Recipes in this book specify which type of canner is appropriate. Find a boiling-water canning tutorial on pages 462–463 and pressure-canning steps on pages 464–465.
Choose the Right Jars: Use jars made specifically for canning. Don’t use glass jars from purchased food, even if they look like canning jars. Don’t use jars that look different from the canning jars currently on the market. And avoid jars with chipped edges, because that can affect the seal. Use the size jar specified in the recipe.
Use Lids Properly: Use the special two-piece lids manufactured for canning. Reuse rings, but do not reuse lids, which have a sticky compound that seals the jar.
Don’t screw lids on too tightly or they won’t create a vacuum seal. Follow the manufacturer’s directions for preparing lids. Test for sealing on each jar after it has cooled (tip, page 463).
Follow the Recipe: Always use tested recipes from reliable, current sources—and follow the recipes exactly. The Better Homes and Gardens® Test Kitchen follows USDA guidelines when creating and testing recipes. Don’t alter ingredients. Alterations can compromise food safety. Also avoid doubling recipes. If you need more than what a recipe yields, it’s always best to make it twice.
Keep It Clean and Keep It Hot: Keep everything scrupulously clean. Wash and sterilize jars. Pack hot food into hot jars one at a time—not assembly-line style. Take only one sterilized jar out of the canner at a time. As soon as it is filled, place it back in the simmering water in the canner.
Adjust for Altitude: Timings in the recipes in this book are for altitudes up to 1,000 feet above sea level. Water boils at lower temperatures at higher altitudes, so follow these directions for adjusting timing:
Blanching: Add 1 minute if you live 5,000 feet or more above sea level.
Canning: Call your county extension service for detailed instructions.
Jellies and Jams: Add 1 minute processing time for each additional 1,000 feet.
Sterilizing jars: Boil jars an additional 1 minute for each additional 1,000 feet.