How to Can and Make Jam

Canning is a technique that can intimidate even the experienced cook. Here, we show you basic canning techniques, using a plum jam recipe. However, the same methods can be used for preserving many other fruits and some vegetables. After you’ve mastered the basics, you can move on to more elaborate recipes. Although preserving can be hot, sticky work, we’re sure you’ll find the rewards are glorious.

The following supplies are sold at hardware stores, supermarkets, and supercenters, or Amazon.com and Freshpreserving.com (the official website of Ball, the consummate canning resource). Expect to pay $40 to $80 for a complete boiling-water canner set.

Boiling-water canner or similarly deep pot (think lobster size)
Canning rack or cake-cooling rack, to fit into the pot
Jars, lids, and bands
Jar-lifting tongs
Headspace-measuring tool
Clean dish towels
Labels
Timer

Check your supplies
Bands should screw evenly over lids; jars should be free of scratches or chips, which could cause seal failure during processing or sealing.

Don’t reuse lids
Jars and bands can be recycled, but the flat lids are onetime use only.

Cool carefully
Never place hot jars directly on kitchen counters; the glass might crack. Use a dish towel or a cooling rack instead.

Makes four half-pint jars

Ingredients:
3 pounds plums (or other stone fruit such as peaches, nectarines, or apricots), pitted and quartered
3 cups organic sugar
1 tbsp. fresh lemon juice
3⁄4 tsp. coarse salt

Wash jars and lids with soapy water, dry bands, and set aside. Place jars in a large pot and cover with water. Bring to a simmer. Put lids in a separate pot of hot water. Leave jars and lids in water until ready to fill.

Combine plums, sugar, lemon juice, and salt in a stockpot over high heat.

Bring to a boil, mashing with a potato masher. Skim scum off top.

Boil, skimming and stirring frequently, until bubbles slow and you can see chunks of fruit showing through top and mixture clings to a spoon, falling off in languid clumps, 10 to 12 minutes. Pick up and discard skins with a fork, if desired.

Lift jars out of hot water one at a time, draining water. Ladle hot jam into hot jars using a wide-mouth funnel, leaving 1⁄2-inch headspace. Slide a nonmetallic spatula or chopstick between jam and jar to release trapped air bubbles.

Wipe rim and threads of jar with a clean, damp cloth. Remove lid from hot water. Place lid on jar. Screw band down evenly and firmly, just until resistance is met.

Place in canner and lower into water. Put lid on canner. Bring water to a boil. Start keeping time after water comes to a rolling boil. Process 1⁄2 pints 10 minutes at a gentle but steady boil.

Turn off heat and remove canner lid. Let canner cool 5 minutes, then remove jars and set them upright on a dry towel or rack. Do not retighten bands. Let jars cool 12 to 24 hours.

Once cool, check lids for a good vacuum seal by pressing on center of each. If center is pulled down and does not flex, remove band and gently try to lift lid off with your fingertips. If lid does not flex and you cannot lift it off, seal is set. Wipe lid and jar surface with a clean, damp cloth to remove food particles and residue. Label. Store jars in a cool, dry, dark place.

See our Jam, Preserves and Jelly Recipes

For more information on canning, visit Ball.