- 12 pints raspberries
- 14 cups sugar
- 1/4 cup fresh lemon juice
- 1 Tbs. lemon zest
Place the raspberries in a large bowl and, using a potato masher, crush them until no pieces remain. Alternatively, crush them in a food processor.
In a large pot, stir together the raspberries, sugar, lemon juice and zest. Place over medium heat and bring to a boil. Cook, stirring constantly, until the sugar dissolves. Increase the heat to high and cook, stirring constantly, until the mixture becomes a thick gel, 20 to 25 minutes. To test the consistency, drop a few drops from a spoon onto a plate. Remove the pot from the heat.
Using tongs or a jar lifter, remove a jar from the water and place on a clean work surface. Ladle jam into the jar to within 1/2 inch of the top. Using a clean, damp towel, wipe the rim clean. Using tongs, remove a lid from the water and place on the jar. Using tongs, remove a lid ring from the water and screw onto the jar until just tightened; do not overtighten. Repeat with the remaining jam and jars. Let the jars stand upright for 10 minutes, then invert them for 1 hour.
Turn the jars upright and check for a good seal; the seal indicator should be depressed. If the seal is not good, invert those jars for 1 hour more and check again. Store all jars in the refrigerator for 1 to 2 months.