Raspberry freezer jam is a sweet and tart jam that's made on the stovetop and stored in the refrigerator or freezer. This small batch recipe makes two 8-ounce jars.
Have you made freezer jam before? Once I started, I couldn't go back to buying store bought jam. My favorites each summer include strawberry jam, peach jam, and pineapple 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. We're also using cornstarch instead of pectin, so there's no need to run to the store for one special ingredient.
Add raspberry freezer jam to your morning toast or a stack of buttermilk pancakes. It also makes a great ice cream topping!
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).
Tips and tricks
Jam look dry? - If your jam begins to look a bit dry and thick, turn the heat down and add a splash of water.
Jam not thickening? - Very juicy, in-season raspberries may require extra cornstarch. Make a slurry of additional cornstarch with a bit of water and add slowly while stirring constantly until incorporated. Continue cooking until your jam has thickened slightly.
Do a spoon test - Does your jam also thickly coat the back of a spoon? It's done and can be removed from the heat.
Storage
Raspberry freezer 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.
To thaw freezer jam, transfer the jar from the freezer to the refrigerator the night beforehand.
Frequently asked questions
This recipe 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.
No, there is no need to sterilize your jars for freezer jam. Sterilizing is done in canning to remove bacteria, yeast, or fungi before filling jars with cooked fruits or vegetables. Canned foods are meant to be stored at room temperature for long periods of time. Those jars need to be free of bacteria so that your food doesn't spoil. Since freezer jam is stored in the refrigerator or freezer at all times, there is no need to sterilize your jars beforehand. It's just like storing any other foods in your refrigerator or freezer. A regular, clean jar is sufficient.
No, freezer jam must be stored in the refrigerator or freezer at all times. This jam recipe is not shelf stable. This recipe is not a replacement for a traditional canning recipe for shelf stable jams.
If you'd like to make a lower sugar jam, add half the amount of sugar. Keep in mind the raspberry flavor will be more pronounced and potentially tart. Do a taste test before transferring your jam into jars.
While I haven't tested it myself, readers have had success using alternative sweeteners with this recipe. If you'd like to make sugar-free jam, replace the sugar 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-sugar or no-sugar jam will not last quite as long when refrigerated.
Freezer jam is cooked quickly on the stovetop and stored in jars in the refrigerator or freezer. Regular jam is canned. Canning involves boiling the jars to preserve and seal them, making them shelf stable. Freezer jam takes less effort but requires refrigeration or freezing to preserve it.
Troubleshooting
The cornstarch listed in the recipe thickens the jam while it cooks. The amount of cornstarch needed depends entirely on the juiciness of your raspberries. Extra juicy, in-season raspberries can release a lot of juices as they cook, which requires more cornstarch to thicken. Out of season grocery store raspberries can be a bit on the dry side in comparison and may require less cornstarch. If your jam isn't thickening, add a slurry of cornstarch, 1 teaspoon at a time, and continue cooking.
If you're using out of season raspberries, maybe purchased at a local grocery store, they're likely to be less juicy than in-season raspberries from a local farmer's market. If this is the case, you may not need any cornstarch at all. I recommend adding a splash of water in step 1 of the recipe if your berries aren't very juicy. I've made many batches of this freezer jam and the amount of cornstarch varies each time. Keep an eye on your jam. If it looks thick and dry, add a splash of water and remove it from the heat once your berries are softened.
Ingredients like fresh fruits can be inconsistent. Some raspberries can be very juicy and sweet, while others can be a little dry and tart. I've made batches of jam with store-bought berries as well as locally farmed in-season berries and the difference is vast. The key is to watch your jam as it cooks. If it looks dry, add a splash of water and turn the heat down. If it looks very wet and juicy, add more cornstarch.
I recommend cooking your jam on the stovetop until it thickly coats the back of a spoon. It will continue to thicken as it cools. If your finished jam is still thin, pour it back into a saucepan and warm over medium-low heat. Make a slurry of a teaspoon of cornstarch and a splash of water and mix into your jam. Cook until the jam thickens, adding more cornstarch as needed.
Larger quantities of jam can take longer to thicken and cook down on the stove top simply because you've got more ingredients in the pot. Give it more time and add more cornstarch as needed to help the jam thicken.
Recommended
📖 Recipe
Raspberry Freezer Jam
Ingredients
- 16 ounces raspberries
- ½ cup granulated sugar, or more to taste
- 1 tablespoon lemon juice
- 1 teaspoon cornstarch, more as needed
Instructions
- 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).
- Jam not thickening? Make a slurry of 1 teaspoon of cornstarch and water, then slowly add to your jam while stirring constantly.
- 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.
Equipment Recommendations
Notes
- Jam too thin?: If your berries are in-season and very juicy, you may need to add additional cornstarch to thicken the jam to your desired consistency. Make a slurry of cornstarch and water, then slowly add to your jam while stirring constantly.
- Test for sweetness: 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.
- Freezing: Leave ½" at the top of the jar to allow the jam to expand slightly when freezing.
- Storage: 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.
- Conversion: 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. Measure your raspberries by weight. Bags of frozen raspberries and raspberries sold in plastic clamshell containers are all labeled by weight.
I can taste the cornstarch. Can pectin be substituted instead?
This recipe is written specifically for cornstarch, but there are plenty of recipes that use pectin! Here's a great one: https://tastesbetterfromscratch.com/raspberry-freezer-jam/
I made this yesterday with fresh black raspberries I picked from my yard. This was super easy to make, and is the best jam I’ve ever had. I definitely recommend this recipe!!
Was the teaspoon of cornstarch actually supposed to be a Tablespoon? I have reheated and added and additional teaspoon per 16oz. of raspberries twice now; waiting to see if the second addition will actually make it jam instead of syrup. 🙂
Hi Cecilia, I find that if my berries are in-season and very juicy, the jam may need a bit more cornstarch to help it thicken up. Feel free to add more until it reaches your desired consistency!
Can I make a double batch at one time?
Yes, this recipe can be doubled.
Hi Heather,
I made another recipe for a raspberry jam and the jam became way too thick. I was using it for a layer in a trifle. Today I again found your recipe and just finished up my jam. I added a bit more lemon juice and some lemon zest. It will be my go too now and I love having homemade jam in the frig!
is there any way to make freezer jam without lemon juice? I just finished 12 pints of blackberry jam with pectin and lemon juice (2 tbl) and although the jam is ok it has an overwhelming taste of lemon and leaves a horrible aftertaste.
Hi Linda, traditional jam recipes that use pectin require the addition of an acid to help the pectin set. Lemon juice also helps keep your jam from discoloring. Freezer jam can be made without lemon juice, since you're not using any pectin (although it may discolor slightly over time).
So what is the amount by cup?
This recipe makes two 8 ounce jars, which equals about two cups of jam.
Is the 16 oz of berries by weight or volume?
Weight
Is this supposed to be simmered uncovered? Thank you
Yes, simmer uncovered.
Getting ready to make my first freezer jam without pectin. One step you did not mention is sterilizing your jars and probably lids too. I'm sure it will be delicious and happy to go without the pectin which hasn't been very reliable lately.
Hi Jan, I hope you enjoy the freezer jam! Since this jam is stored in the freezer, there isn't a need to sterilize the jars - they won't be stored at room temperature. However, you're welcome to add this step as an extra precaution if you like!