Easy, fruity low-sugar raspberry jam is a run and satisfying home canning project. You’ll always be glad to have a supply of berry preserves on hand.
Where I live, late summer is the best eating time of year. Local produce stands pop up on almost every corner. This time of year, I visit my favorite farm stand every day.
I pick up all our favorite summer produce like peaches, corn, summer squash, and watermelon. But my absolute favorite thing to buy is fresh local raspberries, which I use to make low sugar raspberry jam.
I’m a little obsessed with these local fresh raspberries because of their intense, bright, sweet-tart flavor. I think other people in my hometown love them too. They usually sell out early in the day. If I want to get enough raspberries to make enough low sugar raspberry jam for the year, I have to get to the stand right as the delivery truck arrives!
Because I eat this jam almost every morning, I usually make 3-4 batches of homemade raspberry jam every summer. That way, I have plenty for my family and to give away to friends.
Are Fresh or Frozen Raspberries Best?
If you don’t have a favorite local supplier of raspberries, you can use any fresh raspberries or even frozen raspberries for low sugar raspberry jam.
Frozen raspberries are less expensive. Plus they’re frozen the same day they’re picked, so they have great flavor. If you use frozen raspberries, measure them while frozen, then let them thaw before using them in the recipe.
How To Make Raspberry Jam with Less Sugar
My homemade raspberry jam recipe is easy. However you will need a few important pieces of canning equipment.
Equipment for Home Canning
For this easy raspberry preserves recipe, you’ll need:
- Water bath canner with canning rack
- Half-pint Mason jars with lids and rings
- Jar lifting tongs
- Canning funnel
- Magnetic wand for retrieving lids from hot water (optional)
You can find the jars, rings, canners and all the equipment at stores like Walmart or many grocery stores. Or you can order a canning kit, like this Ball Enamel Water Bath Canner with Utensils, from Amazon. Most people only have to buy this equipment once, and it lasts a lifetime. The one exception is the jar lids and rings, which have to be replaced.
You will also need some regular kitchen equipment for this recipe, such as:
- Potato masher
- Large pot, like a soup pot, for boiling the jam
- Wooden spoon or heat-proof silicone spatula, for stirring
- Large spoon for skimming
- Large liquid measuring cup
- Dry measuring cups and spoons
- Small ceramic plates
- Clean kitchen towels
Before you start the canning process, inspect and wash seven half-pint Mason jars. Run your finger around the rim of each jar to make sure it’s not chipped. A chipped jar won’t seal properly. You might not fill all seven jars, but it’s best to have an extra just in case you discover a chip or crack later.
Sterilizing Jars for Homemade Preserves
After you inspect the jars, wash them in the dishwasher or by hand with hot soapy water. Set the clean jars on a drying rack or clean kitchen towel while you move on with the recipe.
Our mothers and grandmothers used to sterilize jars by boiling them for 10 minutes, but this isn’t necessary. The jars will be thoroughly sterilized during the water bath canning process.
In decades past, Mason jar lids needed to be soaked in hot water before using. This step is no longer necessary. Just make sure the lids are clean and dust-free. I wash my lids and rings with hot water, and set them on a clean kitchen towel until I need them.
Once the jars are clean, put 2 small ceramic plates in the fridge, because you will need those later for testing the jam.
Cooking Low-Sugar Raspberry Jam
Next, wash about 8 cups of fresh raspberries. Pick out any leaves you see. Eight cups of whole raspberries should yield 5 cups of mashed raspberries.
This four-ingredient recipe simply calls for fruit, sugar, lemon juice and pectin. Mix the fruit, lemon juice, pectin and 1/4 cup sugar in a large soup pot, and bring it to a full boil.
Then add the remaining sugar to total 3 1/2 cups, and bring it back to a full boil for one minute. A full boil, also called a hard boil, is a boil that doesn’t go away when stirred. Stir the jam the whole time so it doesn’t burn.
You can mash the raspberries with a potato masher or process them in a food processor using the pulse setting. For this jam, I like to use a potato masher.
Once the jam comes to a hard boil a second time for a full minute, test its texture. Remove the jam from the heat. Take one of the cold plates out of the fridge. Pour a small spoonful of jam onto the cold plate. If the jam thickens up to a texture you like, it’s done.
Repeat the one-minute boil if the jam is still too runny after the second test. If it’s too runny after that, you might need to add another 1/4 box of pectin and boil again. (I’ve actually never had to do that.) This batch was perfect after the first test.
Can I Double the Recipe?
If you’re like me and want to make multiple batches of berry jam, I recommend making them one at a time. Doubling or tripling jam recipes will sometimes affect the cooking process. Small-batch means your jars of jam will be as packed with flavor as possible.
What Kind of Pectin is Best?
A key ingredient to this low sugar raspberry jam recipe is low-sugar pectin. You can usually find this in grocery stores where the canning supplies are. Pectin helps the jam thicken. Make sure you get the low sugar pectin and not the regular for this recipe.
Low sugar pectin contains a mold inhibitor, which is necessary for reduced sugar recipes. Many people don’t realize that all of the sugar in regular jam recipes acts as a preservative. So if you’re reducing the sugar, you need to use low sugar pectin to keep it mold-free and safe to eat.
Yes, 3 1/2 cups of sugar is a low-sugar jam recipe! Most jam recipes call for double that! In fact, regular jam like Smucker’s contains more sugar than fruit.
The way I look at low sugar raspberry jam is that it’s a lot of sugar per recipe, but not per serving. A serving of this low sugar raspberry jam is usually one tablespoon, and it will add tons of flavor to your toast, yogurt, or whatever you add it to.
How Thick is Low-Sugar Raspberry Jam?
You might notice that this recipe is different from the one that comes with your box or container of pectin. I use ratios of fruit, sugar and pectin that will make a relatively thick jam, which is what I like. This jam has a spreadable rather than a pourable consistency.
Filling and Sealing the Jam Jars
Once the jam is cooked, use a large spoon to skim off the foam. There’s nothing wrong with the foam, but it doesn’t look pretty.
After skimming, let the jam sit for 10 minutes or so, then stir. This will help distribute the fruit chunks so they don’t float to the top when you jar the jam.
While the jam is resting, line up your clean jars and lids.
Fill the mason jars with a ladle and canning funnel. Make sure to leave about 1/4 inch of “headspace,” or empty space, at the top of the jar, so if the food expands during processing, the lid doesn’t blow off!
Next, wipe off the rims with a clean towel. Place the lids on the jars and secure with rings, but don’t screw them on too tight.
How to Boil Filled Jam Jars
Place the rack inside the water bath canner and fill the pot with water. Place the raspberry jam jars carefully into the canner. The water should cover the tops of the jars by at least one inch. When in doubt, follow the directions that come with your water bath canner.
Processing time depends on how far you are above sea level, so check the recipe below. At the end of the processing time, use the jar lifting tongs to remove the jars from the water, and set them on a clean towel. Let them sit undisturbed for several hours, so they can seal. You know the jars are sealed when the center of the lid is depressed and doesn’t move when you press it with your finger. You might hear a popping sound when the lids seal.
Making your own low-sugar raspberry jam is totally worth the effort! Homemade jam also makes a great neighbor gift. Give it a try and let me know how it turns out!
More Low-Sugar Jam Recipes
- Peach Vanilla Jam (Low Sugar Recipe)
- Low Sugar Peach Jam
- Low Sugar Blueberry Jam
- Low Sugar Strawberry Jam
Low Sugar Raspberry Jam
- 8 cups fresh raspberries to yield 5 cups mashed raspberries (see note for using frozen raspberries)
- 3 ½ cups white sugar
- 1 box low sugar pectin
- 3 tablespoons lemon juice either fresh or bottled
- 6 half-pint Mason jars with lids
- Potato masher
- Large wooden spoon or silicone spatula for stirring
- Large wide pot like a soup pot for cooking
- Water bath canner
- Canning funnel
- Jar lifting tongs
- Sterilize the jars by washing in the dishwasher on the sterilize cycle or immersing in boiling water for 10 minutes. Place clean jars on a clean towel. Put 2 small ceramic plates in the refrigerator, because you will need them later to test the thickness of the jam.
- Wash the raspberries, and pick off any leaves. Mash them with a potato masher, or process carefully with a food processor to get the texture you want. Measure the sugar, and reserve ¼ cup to mix with the pectin.
- Mix the pectin, lemon juice, and ¼ cup sugar in a small bowl or measuring cup.
- Place the raspberries in a large cooking pot, and add the pectin mixture. Over medium high heat, bring everything to a full boil that does not go down when stirred. Stir the entire time so the jam does not burn. At this point, add the rest of the sugar, stir well, and bring the jam back to a full boil for one minute. Turn off the heat and test the thickness of the jam by putting a small spoonful on a cold ceramic plate. If it’s thick enough, it’s done. If it’s too runny, add ¼ package more pectin, bring to a hard boil again for 1 minute, and test again with the second cold plate.
- Let the jam cool for 10 minutes, then stir to distribute the fruit. If the jam is too hot when you put it in the jars, the fruit chunks will float to the top. Meanwhile, place the Mason jar flat lids (not the rings) in very hot (not boiling) water to get them ready.
- Fill your jars, using the ladle and funnel, leaving 1/4 inch of clearance space at the top of the jar.
- Wipe the rims of the jars with a clean, damp towel. Place the lids on the jars and secure with rings. Do not screw the rings on too tight.
- Process the jars, following the instructions for your water bath canner. This jam requires 5 minutes processing at sea level, 10 minutes above 1000 feet altitude and 15 minutes above 6000 feet altitude.
- Remove the jars carefully with the jar lifting tongs, and set them on a clean towel. Leave them undisturbed for several hours or overnight to let them seal. You can tell they are sealed if the center of the lid is depressed slightly and does not move when pressed with your finger. Remove the rings so they don’t rust due to trapped moisture, or if you want to leave them on, at least remove them temporarily to make sure they are dry underneath. The jam lasts about a year in the pantry.
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