How to Make It
Pit and coarsely chop peaches. Measure 4½ cups (1.1 liters) chopped peaches into a 6-quart (6-liter) stainless steel or enameled Dutch oven, and mash with a potato masher until evenly crushed. Stir in pectin and next 3 ingredients.
Bring mixture to a full rolling boil that cannot be stirred down, over high heat, stirring constantly.
Add sugar, stirring to dissolve. Return mixture to a full rolling boil. Boil hard 1 minute, stirring constantly. Remove from heat. Skim foam, if necessary.
Ladle hot jam into a hot jar, leaving ¼-inch (.5-centimeter) headspace. Remove air bubbles. Wipe jar rim. Center lid on jar. Apply band, and adjust to fingertip-tight. Place jar in boiling-water canner. Repeat until all jars are filled.
Process jars 10 minutes, adjusting for altitude. Turn off heat; remove lid, and let jars stand 5 minutes. Remove jars and cool.