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.
It's strawberry season. Now is a great time to stock up on fresh, in-season strawberries. Looking for something new to make with those juicy strawberries? How about a batch of freezer jam!
You'll love this recipe because you only need four ingredients, most of which are probably in your kitchen already. I like to make use of ingredients I have on hand, instead of going out to buy one special ingredient (like pectin). So for this jam recipe, we're using cornstarch instead.
Strawberry freezer jam is perfect for spreading onto your morning toast. It can also be added to other recipes that call for strawberry jam, like no churn strawberry ice cream and strawberry jam popsicles.
Ingredients and substitutions
- Strawberries - Fresh, in-season strawberries are best. Grocery store strawberries, strawberries from your local farmer's market, or strawberries from your home garden all work great. You can also substitute with frozen strawberries that have been thawed.
- Granulated sugar - I have only made this recipe with granulated sugar. I have not made this recipe with sugar substitutes (if you do, please consult your sugar substitute packaging for correct quantities). Sugars acts as a preservative in this recipe, so if you do use a sugar substitute, keep in mind that your jam will not keep as long.
- Lemon juice - Helps cut the sweetness of your jam and adds a bright, fresh element. It also helps prevent the growth of bacteria.
- Cornstarch - Thickens your jam. Omitting the cornstarch will result in a thin strawberry sauce (it will taste just as good, but will not thicken to a jam consistency).
What size jars do I need?
One quart of strawberries makes two 8-ounce jars of jam. I like to use 8-ounce ball mason jars to store my jam.
This recipe is very easy to double, triple, or more - so stock your freezer with as much jam as you'd like. Freezer jam will last about 3 weeks (or longer!) in the refrigerator, or about a year in the freezer.
Do I need to sterilize my jars?
Sterilizing is something that is done in canning to remove any bacteria, yeast, or fungi on your jars before filling them with cooked fruits or vegetables. This is done because canned foods are meant to be stored at room temperature for long periods of time. Those jars need to be free of bacteria, which would cause your food to spoil over time.
Since freezer jam is stored in the refrigerator or freezer at all times, there is no need to sterilize your jars beforehand. A regular, clean jar is sufficient.
This jam recipe is not shelf stable. I repeat - not shelf stable! It must be stored in the refrigerator or freezer, and is not a replacement for a traditional canning recipe for shelf stable jams.
However, if you'd like to sterilize your jars as an additional precaution, you are welcome to do so.
Storing your jam
As I said above, this jam is not shelf stable. Shelf stable goods can be stored in your pantry at room temperature without spoiling. This recipe is a simple freezer jam, and is meant to be stored in the refrigerator or freezer at all times.
Your jam will keep for 3-4 weeks in the refrigerator, or about a year in the freezer. Keep your jar tightly sealed at all times to maximize freshness.
Low sugar jam
If you'd like to make a lower sugar jam, add half the amount of sugar. The strawberry flavor will be more pronounced and tart, so keep this in mind.
If you'd like to make sugar-free jam, replace the sugar called for with your favorite sugar-free sweetener. Consult your sweetener's package directions, as some alternative sweeteners are more concentrated and should not be swapped at a 1:1 ratio.
Sugar also acts as a preservative, so your low- or no-sugar jam will not last quite as long when refrigerated.
Readers have had success using alternative sweeteners with this recipe, although I have not tried any myself.
Strawberry Freezer Jam
- 1 quart strawberries chopped (about 4 cups)
- 1 cup granulated sugar
- 2 tablespoons lemon juice (juice from one lemon)
- 2 teaspoons cornstarch
- In a saucepan over medium heat, add chopped strawberries, granulated sugar, lemon juice, and cornstarch. Stir occasionally until sugar has dissolved (and 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, or until mixture has reduced slightly. The mixture should thickly coat the back of a spoon (and will continue to thicken as it cools).
- 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.
- 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 in a tightly sealed jar, 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.