Makes about 3 cups
I've made jam on the stove top but nothing beats the ease and speed of using the microwave. My microwave is 1000 watts, so keep in mind that cooking times will vary for models with lower or higher power.I've also experimented with homemade pectin, but haven't had success yet. You can read more about that adventure in this post.
2 quarts of strawberries, about 4 cups, washed and hulled
1 cup sugar
2 teaspoons calcium water (included with pectin package – follow directions for making water)
2 teaspoons Pomona's Universal Pectin
In a large glass microwave-safe bowl, mash the berries to desired consistency depending on if you like a smooth or thick and chunky jam. A potato masher does the job perfectly.
Place bowl in the microwave and cook on HIGH until berries are almost boiling, about 3 minutes. Ladle out 1 cup of cooked berries into a bowl; set aside. Add the sugar and calcium water to the bowl with remaining berries, stir well and cook on high for 3 more minutes.
Meanwhile, whisk the pectin powder into the reserved cup of berries. It will look like it's clumping but don't worry. Stir the pectin-berry mixture into the berry-sugar mixture. Cook on high for 3 more minutes, until thick and bubbly. Transfer to a container, let cool and refrigerate for up to three weeks or process in a hot water bath using canning jars.