Yes — you can make a delicious low-sugar raspberry freezer jam. I use a modest amount of honey to lightly sweeten the berries, producing a jam that is pleasantly tart, gently sweet, and full of raspberry flavor. If you don’t use honey, agave or granulated sugar works well too. Most traditional jam recipes call for a large amount of sugar to help the jam set, but this freezer jam sets up nicely with only a fraction of the sweetener. Keep in mind that low-sugar jam is best enjoyed as a condiment rather than eaten by the spoonful straight from the jar.
We’ve grown an ever-bearing raspberry variety called Caroline for about 20 years. These produce heavily for six to eight weeks in summer, then more sparingly until frost — so we always have plenty of berries. We enjoy them fresh by the handful, mixed into oatmeal, cereal, non-dairy yogurt, and fruit salads. I also use them in a fresh raspberry tart and freeze many quarts each season for later.
Over the years I’ve tried many jam methods and recipes. This low-sugar raspberry freezer jam is my favorite. It’s based on Pomona’s Universal Pectin with a small adjustment: I remove about half of the raspberry seeds before combining the berries. That simple step removes the gritty texture that sometimes bothers me while keeping the bright raspberry flavor intact.
My Low-Sugar Raspberry Freezer Jam Recipe
- A modest amount of honey (or agave or granulated sugar) is used to sweeten the jam.
- Seeds are removed from half the berries to improve texture.
- This recipe uses Pomona’s Universal Pectin, which lets you use much less sweetener than commercial pectins that require large amounts of sugar.
Pomona’s Universal Pectin contains 100% pure citrus pectin and is vegan, gluten free, and GMO free. It has no additives, preservatives, sugar, or dextrose, and contains no corn or apple by-products.
The included monocalcium phosphate powder is a food-grade calcium source used to activate the pectin.
Pomona’s Universal Pectin
Method Overview
- Prepare the calcium solution.
- Mix pectin into the sweetener.
- Mash half the raspberries and remove seeds from the other half.
- Combine everything, bring briefly to a boil, then jar and cool before freezing.
How to remove raspberry seeds
The quickest way to remove seeds is with a food mill set over a bowl to collect the juice. Turn the crank until no more juice is released.
If you don’t have a food mill, press the berries through a fine-mesh strainer using the back of a spoon to push the pulp and juice through while leaving the seeds behind. It takes more effort but produces similar results.
2024 UPDATE: I also made a video demonstrating this process.
Low-Sugar Raspberry Freezer Jam
Ingredients
- 1/2 teaspoon Pomona calcium
- 1/2 cup honey or agave (or substitute granulated sugar — see notes)
- 2 teaspoons Pomona pectin
- 8 half-pints fresh raspberries
Instructions
To Prepare the Calcium Water
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Combine 1/2 teaspoon Pomona calcium powder with 1/2 cup water in a jar with a tight-fitting lid. Shake well and set aside; refrigerate any unused portion for future batches.
To Prepare the Sweetener
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Measure the honey or agave and mix it thoroughly with the 2 teaspoons of Pomona pectin. Set aside.
To Make the Jam
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Place 4 half-pints of fresh raspberries in a large, heavy-bottomed pot and mash with a potato masher. Cover and set aside.
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Remove the seeds from the remaining 4 half-pints, reserving the juice. A food mill is easiest, or press through a fine-mesh strainer. Pour the reserved juice into the pot with the mashed berries.
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Add 2 teaspoons of the prepared calcium water to the pot (store the rest in the refrigerator).
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Cook over medium-high heat, stirring frequently, until the mixture reaches a full boil.
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Stir in the sweetener/pectin mixture until fully incorporated.
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Return to a full boil and continue to boil while stirring for 1 minute, then remove from heat.
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Skim any foam from the surface.
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Taste and adjust sweetness if desired: add an additional 1/4 cup honey or agave, stir to combine.
To Freeze the Jam
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Ladle the hot jam into half-pint or pint jars, leaving about 1/2″ headspace to allow for expansion. Seal with lids.
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Cool jars to room temperature before refrigerating or freezing. The jam will not fully gel until it has cooled.
Notes
A half-pint of raspberries is approximately 1 cup.
Jelly is made from fruit juice only, producing a clear, firm gel. Jam contains pulp and sometimes seeds, giving it a looser, more textured consistency.
Once thawed and refrigerated, the jam should keep about three weeks. Always use a clean spoon to prevent contamination.