Raspberry freezer jam is tart, sweet, and made with easy to find ingredients. No pectin required for this recipe, which makes two 8 ounce jars. Keeps in the freezer for up to a year.
Have you made freezer jam before? Once I started, I couldn't go back to buying store bought jam. I make large batches each summer - with my recipes for Strawberry Freezer Jam and Pineapple Freezer Jam.
What I enjoy the most about freezer jam is that you don't need any complicated ingredients or special equipment. It's not as technical as canning, and only takes about 20 minutes to make a batch of freezer jam.
Plus, your freezer jam will keep in the refrigerator for 3 weeks (maybe more), and about a year in the freezer.
Ingredients and substitutions
- Raspberries - Fresh or frozen (thawed beforehand) raspberries can be used to make freezer jam. If using frozen, thawed raspberries, include any juices that are released from your berries while thawing.
- Granulated sugar - Can be substituted with brown sugar. I haven't tried this recipe with sugar substitutes, but they can affect how long your jam stays fresh (sugar helps preserve your jam longer in the refrigerator).
- Lemon juice - Helps cut the sweetness of your jam and adds a bright, fresh element. It also helps prevent the growth of bacteria and discoloration.
- Cornstarch - Thickens your jam. Omitting the cornstarch will result in a thin raspberry sauce (it will taste just as good, but will not thicken to a jam consistency).
Do I need to sterilize my jars?
In short - no. Since this jam is not shelf stable, you do not need to sterilize your jars. Regular, clean jars are sufficient.
Sterilizing is done in canning to remove 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.
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 freezer jam
I store all of my freezer jam in regular 8 ounce ball mason jars. As your jam freezes, like any other liquid, it may expand slightly. I recommend leaving at least ½" at the top of each jar to allow for your jam to expand.
So far, I have not had any issues when freezing my jam in glass jars. If you are concerned about freezing glass, Ball has come out with Ball Plastic Pint Freezer Jars with Snap-On Lids. I haven't tried them myself, but they appear to have good reviews overall.
You can also use any sealable, freezer safe containers you already have on hand.
Freezer jam will keep in the refrigerator for about three weeks. If you don't plan on using an entire jar at once, feel free to toss a partially used jar back into the freezer to keep for longer. Your jam should keep for up to a year in the freezer.
Raspberry Freezer Jam
- 16 ounces raspberries
- ½ cup granulated sugar, or more to taste
- 1 tablespoon lemon juice
- 1 teaspoon cornstarch
- In a saucepan over medium heat, add raspberries, granulated sugar, lemon juice, and cornstarch. Stir until sugar has dissolved.
- Bring to a boil, then reduce heat to medium-low. Simmer for 10-12 minutes, stirring occasionally. Gently mash any large pieces with your spoon as you stir. 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 slightly in the pan. Transfer to jars and allow to cool completely before adding lids. Store for up to 1 year in freezer, or up to 3 weeks in the refrigerator.
- If your berries are in-season and very juicy, you may need to add additional cornstarch to thicken the jam to your desired consistency.
- Test the sweetness of your jam before removing from the heat. This recipe will produce a tart, lightly sweet jam. If you prefer a sweeter jam, add up to double the amount of sugar, or until desired sweetness is achieved. Stir to incorporate, and wait until sugar is dissolved before removing from heat.
- If freezing, leave ½" at the top of the jar to allow the jam to expand slightly when freezing.
- Freezer jam is NOT shelf stable and needs to be kept in the freezer or refrigerator. Treat your freezer jam like fresh produce, it will go bad after a few weeks in the refrigerator.
- 16 ounces of raspberries = about 3.5 to 4.5 US cups of raspberries. Measuring raspberries by the cup can be unreliable due to the varying size and shape of the berries you have on hand. I highly recommend measuring your raspberries by weight. Bags of frozen raspberries and raspberries sold in plastic clamshell containers are all labeled by weight.