Making freezer jam allows you to preserve some of the bounty of summer without the hassle of using traditional canning techniques. Using strawberries in jam is inexpensive if you grow your own or purchase them in bulk when they are on sale. Pectin is a naturally occurring compound in fruits that helps them gel, but additional pectin is usually added to jam to ensure it reaches the desired consistency. If your jam doesn't thicken, there are steps you can take to remedy it so you don't have to waste the fruit.
Measure 1 cup of the unset jam into a bowl. Work with only 1 cup at a time or the ingredients may not combine properly, which prevents setting.
Add 3 tablespoons of sugar and 1 1/2 teaspoons lemon juice to the jam in the bowl. Stir until the sugar dissolves.
Mix 1 1/2 teaspoons of liquid pectin with the jam. Stir for three minutes.
Pour the mixture into a clean freezer container. Mix the rest of the unset strawberry jam 1 cup at a time with the other ingredients until finished.
Place the lids onto the freezer containers once they are filled with jam. Put the containers in the refrigerator until the jam sets, usually within two days. Continue to refrigerate after setting-up, or move the jams to the freezer until ready to use.
If the jam still doesn't set, use it as syrup on pancakes or desserts.
Lack of pectin or acid is usually the cause of improper setting. Always follow the instructions on the pectin package and never leave out the lemon juice. Use fresh lemon juice if it is available.