Classic Strawberry Jam

Ingredients

Instructions

1. 1Wash 8 half-pint canning jars in hot, soapy water and rinse well, or run them through the dishwasher; keep the jars hot in a low oven, in the dishwasher, or in a pot of hot water until you are ready to fill them, since the processing time below is 10 minutes or more and pre-boiling the jars is not required.
2. 2Place the new self-sealing flat lids in a small saucepan, cover with water, and bring just to a bare simmer (not a boil) per the manufacturer's instructions, then keep them warm in the hot water until needed.
3. 3Wash the metal screw bands in warm, soapy water and set them aside at room temperature; they do not need to be heated or sterilized.
4. 4Wash 4 pounds of fresh strawberries under cool running water, drain well, and remove the green caps and hulls.
5. 5Crush the berries one layer at a time with a potato masher (do not puree in a blender or food processor) until you have exactly 4 cups of crushed strawberries.
6. 6Combine the 4 cups of crushed strawberries with 1/4 cup bottled lemon juice in a large, deep stainless steel or enameled saucepot, and stir in the entire 1.75-ounce box of powdered pectin.
7. 7Place the pot over high heat and, stirring constantly, bring the mixture to a full rolling boil that cannot be stirred down.
8. 8Immediately add all 7 cups of sugar at once, stirring constantly, and return the mixture to a full rolling boil; boil hard for exactly 1 minute, stirring the entire time.
9. 9Remove the pot from the heat and skim off any foam from the surface with a metal spoon.
10. 10Ladle the hot jam into the hot half-pint jars, leaving 1/4 inch of headspace at the top of each jar.
11. 11Run a non-metallic spatula or bubble remover tool around the inside of each jar to release trapped air bubbles, adding a bit more jam if needed to maintain the 1/4 inch headspace, then wipe each rim clean with a damp paper towel before centering a warmed lid on the jar and screwing on a band until fingertip tight.
12. 12Load the jars into a boiling-water canner, making sure they are covered by at least 1 to 2 inches of water, cover the canner, and bring the water to a full rolling boil; process half-pint jars for 10 minutes and pint jars for 10 minutes, starting your timer only once the water has returned to a full rolling boil after the jars go in.
13. 13If you live at 1,001-3,000 feet elevation, add 5 minutes to the processing time; at 3,001-6,000 feet, add 10 minutes; at 6,001-8,000 feet, add 15 minutes; and above 8,000 feet, add 20 minutes.
14. 14Turn off the heat, remove the canner lid, and let the jars sit in the water for 5 minutes, then use a jar lifter to transfer them to a towel-lined counter and let them cool undisturbed for 12 to 24 hours, away from cold drafts.
15. 15Once cooled, press the center of each lid to check the seal; it should be concave and should not flex or pop. Remove the bands, wipe the jars down, and label each one with the contents and the date.
16. 16Store sealed jars in a cool, dark place for up to 1 year for best quality; refrigerate after opening and use within about 3 weeks.
17. 17For safety, do not reduce the sugar or alter the ratio of fruit, lemon juice, and pectin in this recipe, since those exact proportions are what make the jam both safe and properly set.