Low Sugar Blackberry Jam Recipe (Easy Canning, Less Sugar)

Late summer means blackberry season and this low sugar blackberry jam recipe is my go-to use for blackberries! This easy recipe for delicious jam uses fresh blackberries, less sugar than the average jam recipes, and pectin. I love canning low sugar blackberry jam to add to toast, or our favorite – yogurt bowls in the morning!

Blackberry jam recipe low sugar

Blackberry jam is super easy to make because you don’t have to cut or peel the fruit. You simply wash it, mash it with a potato masher, and gently cook your blackberry puree.

Most ‘low sugar jam’ recipes still call for 4 cups of sugar. Traditional jams use even more. That is a ton! Not in this low-sugar version.

My blackberry jam recipe low sugar still lets the fresh berries shine. Fruit is naturally sweet on its own, and with the minimal amount of added sugar, we’re simply enhancing the natural sweetness you get in fresh summer berries.

If you love jams that aren’t overly sweet, check out my easy strawberry chia jam too! No water bath is required and it’s ready quickly whenever the low or no sugar jam cravings hit!

What type of blackberries to use

Wild blackberries are what I use most often because they grow like weeds here in Washington state. These blackberries have more seeds than the kind you’d buy at the grocery store.

For the best flavor, choose ripe, in-season blackberries. Both wild and cultivated berries work – just note wild blackberries often create a more seedy jam. If you want a smoother seedless blackberry jam, see my tips below.

You can purchase blackberries, or pick what you find – any will work! Going to a U-pick farm is a really fun option as well if those are near where you live.

What you’ll need for canning jam at home

• water bath canner pot with lid
• jar grabber
• jar funnel
• glass canning jars
• lids
• rings
• large pot for cooking your jam
• large spoon and ladle

This 8-piece canning kit comes with everything you’d need to get started!

Types of pectin to use in this homemade blackberry jam recipe

I’ve worked with 2 kinds of pectin and I really like the results from both.

The one that is really accessible and easy to find at any grocery store is Sure Jell low sugar pectin.

The other kind that allows me to use even less sugar is pomona’s pectin. It is not as easy to find at most grocery stores, but easy to buy online!

Ingredients for this blackberry jam recipe low sugar

Scroll down to view the recipe card below for the full ingredients list, nutritional information, and step-by-step instructions.

• Blackberries – Fresh or frozen both work, but fresh in-season berries give the most vibrant flavor.
• Low sugar pectin – Allows you to use far less sugar while still getting a perfect set.
• Natural cane sugar – Just enough to balance tartness and help with preservation. You’ll use less than traditional jam recipes, keeping this a truly low sugar jam.

How to make this easy blackberry jam recipe

Scroll down to view the recipe card below for the full ingredients list, nutrition facts, and step-by-step instructions.

Step 1: Sterilize the jars – Begin by filling your large canning pot with water. You will want enough water that it will still cover the jars with 1 inch of water above them once they are placed in there. It’s a good idea to start this step early since it takes the longest to come to a gentle boil.

Step 2: Once your water is close to a boil, place your glass jars in the water for 10 minutes. After that remove with tongs and place jars on a clean towel. You can also wash the canning jars with hot soapy water, but I prefer to clean them with boiling water to ensure there is no residue left on the glass, and then they are warm and ready to be used.

Step 3: Place your lids in a small bowl and cover with hot water for 1 minute, then remove and let the lids air dry at room temperature.

Step 4: Make the jam – In a large pot add the blackberries and mash with a potato masher over medium-high heat. In a small bowl mix together the pectin and 1/4 cup sugar. Add the pectin-sugar mixture to the blackberries. Bring to a full rolling boil and stir in the remaining amount of sugar. Allow the mixture to thicken for 1 more minute while boiling, and then remove from heat. You can test if the jam will set well by doing the spoon test – dip a spoon into the hot jam and if it does not slide off the spoon right away and shows jam wrinkles when it dries, your jam is at the perfect gel stage.

Step 5: Fill jars – Ladle the jam into your prepared jars (use the jar funnel to make it less messy). Wipe the rims down (a clean jar rim is a necessity!), and place your lid on, then screw the ring on next. Don’t overtighten the ring.

Step 6: Process jars – Place the jars of jam into the boiling water canner and process for 10 minutes. After 10 minutes remove the jars and allow them to cool on a clean towel. Not too long after you take them out you’ll begin to hear popping – that’s the jars sealing! After they are completely cool, check to make sure they are all sealed. If you press down on the center of the lid it should not spring back. If it does, refrigerate the jar or use the troubleshooting tips down below.

If Your Jam Doesn’t Seal

Sealing issues happen to everyone – don’t worry if one of your jars doesn’t pop the first time! A few common reasons why lids don’t seal:

• The ring wasn’t tightened quite right.
• The jar rim wasn’t completely clean, so the rubber couldn’t grip properly.
• Sometimes it’s just a faulty lid (it happens!).

How to Fix an Unsealed Jar

1. Remove the lid that didn’t seal.
2. Wipe the jar rim thoroughly with a warm, clean washcloth.
3. Place on a fresh lid and secure with a ring.
4. Process the jar again in a boiling water bath for 5 minutes.
5. Remove and listen for that satisfying POP!

If It Still Doesn’t Seal

You can also freeze the jam: let the jar cool completely, leave the lid off while it freezes solid (to prevent cracking), then add the lid and store in the freezer for up to 6 months.once fully frozen add the lid and keep frozen for up to 6 months.

Don’t toss it! Once cooled, pop the jar in the fridge and enjoy within a week.

Best size jars to use for jam

Depending on how quickly you’ll use the jam will determine the size you should choose.

I try and use my freshly opening canned jams within 2 weeks. For big families that use a lot of jam, a large size like a quart mason jar will work.

A great size to avoid waste are half pint jars, and also pint jars.

For a great gifting size, try 4oz canning jars – they are the cutest!

How to make this a seedless blackberry jam

Want to avoid seeds in your low-sugar blackberry jam? Here’s what you do.

After mashing the blackberries you’ll want to press through a food mill or fine mesh strainer to remove the excess seeds.

You can remove all the seeds and make them super smooth like a blackberry jelly, or remove a small amount.

After the number of seeds you’d like to remove have been taken out of the blackberry puree, continue on with adding the sugar and pectin and making your jam!

How we like to use this low sugar blackberry jam recipe

The flavor of blackberries in this jam is delicious and loved by everyone in the family. We put it on toast or whole wheat drop biscuits – both a classic way to use it!

We love to add jam into our plain yogurt to naturally sweetened it. Add some homemade granola – like this hemp granola, and you’ve got yourself a healthy breakfast that’s ready in minutes!

More canning low sugar recipes you’ll love

• Low sugar strawberry rhubarb jam
• Canned peaches in light honey syrup

If you try this low sugar blackberry jam recipe, I’d love it if you left a star rating and comment below letting me know how it turned out!

XO

Heather

Originally published August 2013. Updated October 2025.