Low Sugar Blueberry Jam (Fresh Berry Flavor)

This week we’re featuring fruit recipes, because we had a ton of leftover fruit in the house! My 18-year-old daughter Abby threw a 4th of July party, and apparently she thought the occasion called for buying massive quantities of red and blue berries. Once the party was over, I realized I had a great opportunity to make my favorite low sugar blueberry jam.

Low Sugar Blueberry Jam in Mason Jars

Making homemade jam is pretty easy, but you will need a little bit of canning equipment:

• Water bath canner with canning rack
• 1/2 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. Use new flat canning lids for each batch; clean, undamaged bands can be reused.

You will also need some of your regular kitchen equipment for this recipe:

• Colander
• Potato masher
• Large, open 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
• Ladle
• Small ceramic plates
• Clean kitchen towels

Before you begin, inspect and wash 6-7 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. After you inspect the jars, wash them in the dishwasher, or by hand with hot soapy water. Set the clean jars aside on a drying rack or clean kitchen towel.

Prepare the jars and lids

For any boiling-water process shorter than 10 minutes, sterilize empty jars by boiling for 10 minutes below 1,000 feet, adding one minute per additional 1,000 feet. Keep jars hot until filling. A dishwasher wash alone is not sufficient for this short process. See NCHFP jar-sterilizing guidance.

Once the jars are clean, put 2 small ceramic plates in the fridge, because you will need those later for testing the jam.

Next, wash about 8 cups of fresh blueberries, and pick out any stems that might be sticking to them. Eight cups of fresh blueberries should yield 5 cups of mashed blueberries, which is what you need for this recipe.

You can mash the blueberries with a potato masher, or process them in a food processor using a pulse setting. For this jam, I mashed the blueberries with a potato masher, but later I thought the jam was too chunky, so during cooking I blended it a little bit with an immersion blender.

Low Sugar Blueberry Jam

A key ingredient to low sugar jam is low sugar pectin. You can usually find this in grocery stores near where the canning supplies are. Pectin helps the jam thicken. Make sure you get the low sugar pectin and not the regular.

Low-sugar pectin helps the jam gel with less sugar; it does not make jam mold-proof. Use the exact pectin product specified in a tested canning recipe. Different brands, package sizes and regular versus low-sugar pectin are not automatic substitutes.

This recipe simply calls for fruit, sugar, lemon juice and pectin. Mix the fruit, lemon juice, pectin and 1/4 cup of sugar in a large soup pot, and bring that to a full boil. Then add the rest of the 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 entire cooking time so it doesn’t burn.

Low Sugar Blueberry Jam

Yes, 3 1/2 cups of sugar is a low sugar jam recipe! A regular jam recipe would call for 7 cups of sugar! Regular jam is more sugar than fruit. The way I look at low sugar blueberry jam is that it’s a lot of sugar per recipe, but not per serving. It has so much flavor that you’re not going to eat a lot at once.

This jam uses mashed blueberries for a spreadable texture. The original generic box of pectin does not identify a current tested canning formula. For pantry storage, follow a tested recipe matched to your exact product, including its ingredient proportions and processing instructions. If you cannot confirm a matching formula, cool promptly and refrigerate or freeze the jam instead.

Once the jam has come to a hard boil a second time for a full minute, you can test its texture. Remove the jam from the heat, and take one of the cold plates out of the fridge. Pour a small spoonful of jam on the cold plate. If the jam thickens up to a texture you like, it’s done.

Low Sugar Blueberry Jam in a Plate

Jam continues setting as it cools. If a cooled batch stays too soft, use the pectin manufacturer’s tested remake directions rather than guessing at extra pectin or boiling time.

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.

Skim the foam and stir gently to distribute the fruit. Keep the jam and jars hot for filling; do not leave the jam to cool for 10 minutes before packing. Prepare clean lids according to the manufacturer’s instructions.

Fill the jam jars using 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!

Low Sugar Blueberry Jam in Jars

Wipe off the rims of the jars with a clean towel. Place the lids on the jars and secure with rings, but don’t screw the rings on too tight.

Place the rack inside the water bath canner and fill with water. Place the jars carefully in the canner. The water should cover the tops of the jars by at least one inch. Follow the directions that come with your water bath canner.

For shelf-stable storage, use the altitude-adjusted processing time in a tested blueberry-jam recipe matched to your pectin and jar size. Follow the canner’s cooling directions, then leave jars undisturbed for 12–24 hours before checking seals. Refrigerate unsealed jars promptly.

Making your own 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!

Low Sugar Blueberry Jam in Jars

Low sugar blueberry jam tips

Can I use frozen blueberries?

Thaw unsweetened blueberries before mashing, then measure the 5 cups of prepared fruit the recipe calls for. This is a cooked jam; a no-cook freezer jam uses different instructions and pectin.

Measure the berries after mashing

The recipe needs 5 cups of mashed blueberries. Whole berries leave air gaps in a measuring cup, so 8 cups is only a starting estimate. Wash the berries, remove any stems, then mash and measure.

Is this sugar-free blueberry jam?

No. The recipe uses 3 1/2 cups of sugar. To make no-sugar-added jam, choose a tested recipe designed for the specific no-sugar-needed pectin you are using.

Make one batch at a time

Keep the original batch size rather than doubling the pot. Larger batches heat and evaporate differently, which can affect the set. Prepare a second separate batch if you need more.

Storage after opening

Refrigerate opened jars and use a clean spoon. Lower-sugar spreads may lose quality sooner than regular jam. Discard the entire jar if mold, fermentation or other spoilage appears. See NCHFP jam storage guidance.

Try another fruit with low sugar peach jam or low sugar blueberry jam.

Low Sugar Blueberry Jam

Marsha Maxwell

It's easy to make your own low sugar blueberry jam, with tons of fresh fruit flavor! Try it, and you'll never want to go back to store bought!

4.47 from 58 votes

Print Recipe Pin Recipe

Prep Time 1 hour hr

Cook Time 30 minutes mins

Total Time 1 hour hr 30 minutes mins

Course Sauces & Spreads

Cuisine American

Servings 6 cups

Calories 69 kcal

Equipment

Ingredients

  

For the jam:

• 8 cups whole raw blueberries to yield 5 cups mashed blueberries.
• 3 ½ cups white sugar
• 1 box low sugar pectin
• 3 tablespoons lemon juice either fresh or bottled

Equipment:

• 6 half-pint Mason jars with lids
• Potato masher
• Ladle
• 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

Instructions

 

• Wash and inspect six half-pint canning jars. For a processing time under 10 minutes, sterilize empty jars in boiling water for 10 minutes below 1,000 feet, adding 1 minute for each additional 1,000 feet of elevation. Keep jars hot until filling; a dishwasher wash alone is not sterilization for this short process. Prepare lids according to their manufacturer. Chill two small ceramic plates for checking the jam.
• Wash the blueberries, and pick off any stems. 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 blueberries 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. Remove from the heat. Jam continues setting as it cools; a cold-plate test is an early texture check. If a cooled batch is too soft, follow the pectin manufacturer’s tested remake directions rather than adding an arbitrary extra amount.
• Skim off foam. Keep the jam hot for filling; gently stir to distribute the fruit. Have clean lids ready according to the lid manufacturer’s directions. Do not leave the jam to cool before packing it into hot jars.
• 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.
• For shelf-stable storage, use a tested blueberry-jam recipe matched to your specific low/no-sugar pectin, including its ingredient proportions, jar size, headspace and altitude-adjusted processing time. Pectin brands and package sizes are not interchangeable. Do not assume this older recipe’s generic box measure establishes a tested canning formula. If you cannot confirm a matching tested formula, cool promptly and refrigerate or freeze the jam instead of storing it in the pantry.
• For jars processed using a matching tested canning formula, turn off the heat, remove the canner lid and wait 5 minutes before lifting the jars upright onto a towel. Cool undisturbed for 12–24 hours, then check seals and remove the bands. Refrigerate unsealed jars promptly. Label and store properly processed, sealed jars in a cool, dark, dry place; use within a year for best quality. Refrigerate after opening and discard the entire jar if mold or other spoilage appears.

Notes

Measure 5 cups of mashed blueberries; the 8-cup whole-berry quantity is an estimate. This recipe contains added sugar. Do not substitute regular pectin or omit sugar without switching to a tested recipe designed for that product.

For shelf-stable canning, follow a tested recipe matched to your exact low-sugar pectin, including its ingredient proportions, jar size and altitude-adjusted processing time. If no matching formula is confirmed, cool promptly and refrigerate or freeze the jam instead. Refrigerate after opening; discard the entire jar if mold or other spoilage appears.

Keyword blueberry jam, blueberry jam frozen berries, homemade blueberry jam, low sugar blueberry jam

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