How to Make Jam for Canning
Cook fruit with sugar (and pectin if needed) until it reaches setting point, then fill jars and process in a water-bath canner for the time a tested recipe specifies. Jam is high-acid, so water-bath canning is the correct, safe method.
Jam is many people's first canning project, and a good one: high-acid, forgiving, and deeply satisfying. The two parts are getting a good set, and sealing it safely for the shelf.
Getting a set
Jam sets when fruit, sugar and pectin reach the right balance and temperature. High-pectin fruits (like citrus and some berries) set readily; low-pectin fruits need added pectin or a longer cook. Cook to setting point, checked with a thermometer at the gel stage or the cold-plate wrinkle test.
Canning it
- Fill hot jars with hot jam to the specified headspace; wipe rims.
- Apply lids and bands.
- Process in a water-bath canner for the tested time, adjusted for altitude.
- Cool undisturbed and check seals.
Learn the full method in how to water-bath can. A food mill helps for seedless or smooth fruit. Also try pickles.
- National Center for Home Food Preservation (NCHFP) — tested home-preservation methods and the USDA Complete Guide to Home Canning
- USDA Food Safety and Inspection Service (FSIS)
- U.S. Food & Drug Administration (FDA) — Food
- FoodSafety.gov
Frequently asked questions
Can I water-bath can homemade jam?
Yes. Jam is high-acid, so water-bath canning is appropriate. Follow a tested recipe for the processing time and adjust for altitude.
Do I need pectin for jam?
It depends on the fruit. High-pectin fruits set on their own; low-pectin fruits need added pectin or a longer cook. Tested recipes tell you which.
How do I know jam has reached setting point?
Use a thermometer (around the gel stage) or the cold-plate test, a spoonful on a chilled plate wrinkles when pushed. Recipes describe the method.