Strawberry freezer jam is a simple four-ingredient recipe (no pectin required) that's perfect for strawberry season. This small batch recipe makes a sweet jam that's filled with fresh strawberry flavor. Recipe makes about two 8-ounce jars.
In a saucepan over medium heat, add chopped strawberries, granulated sugar, lemon juice, and cornstarch. Stir occasionally until sugar has dissolved (add a splash of water if your strawberries are not very juicy). Bring to a simmer, then reduce heat to medium-low. Simmer for 10 minutes, stirring occasionally.
Remove from heat and gently mash strawberries with a potato masher until desired consistency is reached. Return to heat and cook for another 5-7 minutes.
Jam not thickening? If you're using very juicy, in-season strawberries, you may need additional cornstarch. Make a slurry of water and cornstarch (start with 1 teaspoon and add more if needed). Slowly pour slurry into jam mixture stir constantly until incorporated.
Jam is ready when it thickly coats the back of a spoon and has a glossy appearance. Jam will also continue to thicken as it stands.
Remove from heat and allow to cool before transferring to jars. When filling jars, leave about 1 inch of space at the top - your jam will expand slightly when frozen. Cool jam completely before adding lids.
Store for up to 1 year in freezer, or up to 3 weeks in the refrigerator.
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Notes
If you're using very juicy, in-season strawberries, you may need to add extra cornstarch to achieve the proper texture. Add extra cornstarch, 1 teaspoon at a time, stirring until dissolved.
Freezer jam is not shelf stable and needs to be stored in the refrigerator or freezer at all times. Jam will keep in the refrigerator for 3-4 weeks or in the freezer for up to a year.
Sugar can be substituted with a sweetener alternative, but please consult your sweetener package for proper ratios (some are more concentrated than others).
If using a sugar substitute, keep in mind that the sugar helps preserve the jam, so your sugar-free jam will not keep as long in the refrigerator.
When doubling or tripling this recipe, your jam will take longer to cook and thicken.