It’s summer and strawberries are showing up on sale in the supermarket. Although homegrown berries or berries purchased from the local farmer’s market could produce a particularly tasty jam, fresh berries in season from a supermarket will do just fine.
- 8 cups whole, fresh strawberries
- 7 cups sugar
- 4 tablespoons lemon juice
- 1 package (1.75 ounces) powdered fruit pectin
Clean eight to ten 8-ounce jam jars and place on a rack in a boiling-water canner. Fill the pot and jars with enough water to cover the top of the jars by an inch. Cover and bring to a simmer (180 degrees Fahrenheit) over medium heat. Do not boil.
Place lids in a small saucepan and cover with water. Bring to a simmer (180 degrees Fahrenheit) over medium heat. Do not boil. Keep the jars and lids warm until ready to use.
Measure the sugar into a bowl and set aside. Then, wash the strawberries and remove the hulls with a sharp knife. Crush the berries slightly with a potato masher in a large bowl. Transfer 5 cups of crushed berries into a large, 2-quart pot.
Add lemon juice to the strawberries in the pot. Whisk in the pectin until dissolved and bring the strawberries to a rolling boil over high heat, stirring frequently. Add sugar and continue stirring until the mixture returns to a full rolling boil that is difficult to stir down. Stir on a hard boil for 1-2 minutes, then remove from the heat and skim foam off the top with a slotted spoon.
Use a funnel to fill one prepared jar at a time. Ladle the hot jam into each jar, leaving 1/4 inch of headspace. If the jam is thick, insert a small rubber spatula between the jam and the inside of each jar to remove air bubbles. Clean the rim of each jar with a damp cloth, if necessary, and cover it with a prepared lid. Place a screw band on each jar and tighten until resistance is met. The screw band should be tight enough to seal the jar, but not so tight that air cannot be released during the canning process. Return each jar to the canner and repeat until all jam has been used.
When all of the jars have been filled and returned to the pot, add additional water (if necessary) to cover them by an inch. Cover and bring to a rolling boil over high heat. As soon as the water reaches a rolling boil, set a timer for 10 minutes to let the jam process. Once the timer goes off, remove the lid and turn off the heat. Let the jars sit in the canner for 5 minutes; then remove them (without tilting) and place on a towel to cool, undisturbed, for 24 hours.
After 24 hours have passed, check to make sure that the jars are properly sealed. A sealed jar will have a concave lid and won’t budge when pressed. Immediately refrigerate or reprocess any jars that haven’t sealed. Loosen or remove the screw bands and store sealed jars in a cool, dry, and dark place. Gift as gifts or use in recipes like these peanut butter and jelly blondies.
Note: canning and preserving can be an extremely finicky and potentially dangerous process. Jams don’t always turn out as thick or as thin as you’d like; and they often won’t reach their final consistency for days after being processed. If the jam is thick, then you might use it as a filling for tarts. If it is too then, then use at as a syrup for waffles or pancakes. When you open a sealed jar, you should still feel a great deal of resistance. If the lid comes off easily and/or the jam looks or smells funny, don’t use it!