Successful home canning starts with jars & lids
by Ann Hamilton, UNH Extension In addition to quality food, successful canning starts with the use of jars in good condition and new lids with new or used ring bands in good condition. Regular and widemouth Mason-type, threaded, home-canning jars with self-sealing lids are the best choice.
They come in half-pint, pint, 1.5pint, quart and half-gallon sizes.
Half-gallon jars should only be used for canning very acid juices. Some jelly jars do come in smaller sizes and are processed according to the recommendations in the recipe – usually following the guidelines for half-pint jars.
Canning Jars
Canning jars in good condition are reusable for years. Check them for nicks, cracks and hairline factures before they are used.
Small nicks on the rims of the jars can result in the lid failing to seal properly. Bail-wire jars with rubber gaskets are not recommended for canning. Bail wire jars have not been made in the U.S. since the early 1960s.
After checking your jars for imperfections, it’s time to get them ready for use. Wash empty jars in hot, soapy water and rinse well by hand, or wash in the dishwater.
Keep jars warm/hot until they are filled with food. You want to avoid filling cold jars with hot food. The jar could crack.
Jar Sterilization
All jars used with jams, jellies and pickled products processed for less than 10 minutes need to be sterilized. To sterilize, place the jars in the canner and fill jars and the pot with hot water to one inch above the jars. Boil the jars for 10 minutes.
Increase boiling time by an additional one minute for every 1,000 feet above sea level.
Lids & Bands
Prepare the lids according to the manufacturer’s instructions.
This is important because several years ago, manufacturers such as Ball changed the design of lids to increase rust resistance and seal-ability and most lids no longer need to be preheated. Boiling or heating lids can contribute to seal failure.
Flat metal lids are meant to be used once than tossed after the jar of food has been used. Ring bands in good condition can be reused year after year if they are not misshaped or rusty. Wash both lids and bands prior to canning. Tighten bands on the jars until finger tight. Don’t overtighten because air won’t be able to escape jars causing contents to darken and lids to buckle and jars to break. Too little tightening can lead to liquid loss in jars and seal failure.
Once the jars of food are processed, do not retighten the bands. Leave them alone while the jars cool for 12 – 24 hours. The seal will form and strengthen as the jar cools. Once the jars have cooled, remove the ring bands, wash, dry and store for the next time you can.
You do not need to store jars of food with the band on since the seal on the jars will be enough to keep the food inside the jars safe. Gently wash the jars with hot, soapy water, rinse and dry before storage.
Unsealed jars of food may be reprocessed within 24 hours using a new lid. You can also store them in the refrigerator and use them within a few days or freeze the contents in freezer safe packaging.
The last thing is marking the lids with contents, date and batch number. A batch number is useful if canning more than one batch per day.
If something were to go wrong with the seals, you would know which other products were canned in the same batch.
Recent research using reusable plastic canning lids (such as the Tattler brand) suggests that reusable lids will seal jars safely when used for home canning. This type of reusable lid also requires a thin rubber gasket. A traditional metal screw band also is needed during canning.
Follow the manufacturer’s instructions for use explicitly. Manufacturers’ instructions may instruct the user to tighten the metal band immediately upon removal from the canner. If instructed, you should do so. Tightening the screw band ensures that the gasket forms a seal. The metal screw band is removed once the container is cooled, and a seal has formed.
