Return mixture to a rolling boil that cannot be stirred down. Boil hard for 1 minute, stirring constantly. Remove from heat. Skim off foam, if necessary.

Ladle hot jam into a hot jar, leaving ¼-inch headpsace. Remove air bubbles. Clean jar rim. Center lid on jar and adjust band to fingertip-tight.

Place jar on a rack in the boiling-water canner. Repeat until all jars are filled. Water must cover jars by at least 1-inch before processing.

Bring water to a full rolling boil over medium-high heat. Cover canner, and process jars for 10 minutes (time starts when full boil begins).

Turn off heat, remove cover, and let jars cool in the water for five minutes. Then, remove the jars from the canner, and place on a towel on the counter to cool completely—do not retighten any bands that have loosened.

Cool 12 hours. Check lids for seal after 24 hours. Lid should not flex up and down when center is pressed. Label and store jars. Any jars that have not sealed should be stored in the fridge and eaten within a week.