Prepare boiling water canner, heat jars in simmering water until ready to use, do not boil. Wash lids in warm, soapy water and set aside with bands.

Wash apricots under cold running water; drain. To peel apricots, blanch in boiling water 30 to 60 seconds. Immediately transfer to cold water. Cut off peel.

Cut apricots in half lengthwise; remove pits and fibrous flesh. Coarsely chop apricots, then crush using a potato masher. Measure 2 quarts crushed apricots.

Combine crushed apricots, lemon juice, and sugar in a large saucepan. Over medium heat, bring mixture slowly to a boil, stirring until sugar dissolves.

Increase heat to medium-high and cook rapidly to gelling point (220°F), stirring to prevent sticking, about 40 minutes. Remove from heat. Skim off foam if necessary.

Ladle hot jam into a hot jar, leaving ¼-inch headspace. Remove air bubbles, Clean jar rim. Center lid on jar and adjust band to fingertip-tight. Place jar on the rack elevated over simmering water (180°F) in boiling-water canner. Repeat until all jars are filled.

Process the Jam: Lower the rack into simmering water. Water must cover jars by 1 inch. Adjust heat to medium-high, cover canner and bring water to a rolling boil. Process pint jars 15 minutes (adjusting for altitude). Turn off heat and remove cover. Let jars cool 5 minutes. Remove jars from canner; do not retighten bands if loose. Cool 12 hours. Check seals. Label and store jars.