This is the basic recipe and procedure Angela Towle uses. It makes about 9 half-pints of jam.4 1/2 cups crushed blueberries (about three pints whole berries) 2 tablespoons fresh lemon juice 7 cups sugar (level cups) 2 pouches pectin (6 oz. total) Wash jars, lids, and bands. Place jars on rack in large pot; place lids in small saucepan. Cover jars, lids, and bands with water. Boil both 10 minutes. Keep in hot water. Meanwhile, remove stems from about 3 pints of blueberries. Crush in small amounts. (If you're using a food processor, chop; do not puree.) Put fruit into 6-to-8 quart pot. Add lemon juice. Measure sugar into a bowl, then stir into fruit. Mix well. (If you wish, add 1/2 teaspoon butter or margarine to reduce foaming when it boils.) Bring fruit mixture to a full, rolling boil over high heat, stirring constantly. Stir in pectin. Bring to full rolling boil again, stirring constantly. Continue to boil for another minute. Keep stirring. Remove from heat. Skim off any foam with large metal spoon. Take jars out of pot. Empty water and shake out excess, but do not wipe inside. Fill all jars immediately to 1/4 inch of tops. Wipe off jar rims and threads. Cover quickly with lids. Screw bands on tightly, then back off 1/4 turn (so air can escape when boiling). Boil the jam-filled jars on a wire rack in a pot (or in a special canning pot) for five minutes. Water should be one or two inches above top of jars. Take jars out carefully and screw covers on very tightly. Cool and label. Check seals: Lids should be curved down or remain so when pressed. Always use new lids.