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How to Make and Can Blackberry Jam
To make and can blackberry jam, you start by combining fresh or frozen blackberries with sugar and lemon juice, cooking the mixture down until it thickens, and then processing the filled jars in a boiling water bath for long-term storage.
It sounds like a lot of work, but once you learn how to make and can blackberry jam, it becomes one of those satisfying kitchen rituals you actually look forward to every summer.
If you’ve ever wondered how to make and can blackberry jam without a bunch of fancy equipment, you’re in the right place.
In this post, we’ll walk through how to make and can blackberry jam step by step, including the tools you need, the cooking process, and the water bath canning method that keeps your jars shelf-stable for a year or more.
Let’s dive in and get those jars ready.
Why Making and Canning Blackberry Jam Is Worth It
Learning how to make and can blackberry jam is worth the effort for a few big reasons.
You Control the Ingredients
When you make and can blackberry jam at home, you decide exactly what goes in the jar.
No high fructose corn syrup, no artificial pectin fillers, and no mystery preservatives.
Just berries, sugar, lemon juice, and maybe a little pectin if you like a firmer set.
That’s it.
Blackberries Are Loaded with Flavor and Nutrients
Blackberries bring a deep, tart-sweet flavor that shines in homemade jam.
They’re also rich in vitamin C, fiber, and antioxidants, so the jam you make and can blackberry jam with retains at least some of that goodness.
Plus, when you make and can blackberry jam during peak berry season, you lock in that fresh-picked taste for the middle of winter.
Canning Makes Your Jam Shelf-Stable
The reason to can blackberry jam instead of just storing it in the fridge is shelf life.
A properly processed jar of blackberry jam can sit in your pantry for up to a year.
That means you can make and can blackberry jam in July and still be enjoying it next spring.
How to Make Blackberry Jam Step by Step
Before you make and can blackberry jam, gather your ingredients and tools so the process flows smoothly.
Gather Your Ingredients
For a classic batch, you’ll need about 8 cups of fresh or frozen blackberries, 5 to 6 cups of granulated sugar, and 1/4 cup of lemon juice.
If you like a firmer jam, add one box of powdered pectin, though blackberries do contain natural pectin and will set on their own with enough cooking.
Cook the Berries Down
Start by crushing your blackberries with a potato masher or giving them a quick pulse in a food processor.
You want some texture left, not a smooth puree.
Combine the crushed berries, sugar, and lemon juice in a large heavy-bottomed pot.
Bring the mixture to a rolling boil over medium-high heat, stirring constantly so it doesn’t scorch.
Test for the Right Set
The hardest part of learning how to make and can blackberry jam is knowing when it’s done.
Spoon a little jam onto a chilled plate and pop it in the freezer for a minute.
If it wrinkles when you push it with your finger, it’s ready.
You can also use a candy thermometer, aiming for about 220°F (104°C) at sea level.
Skim and Fill Your Jars
Once your jam has reached the right consistency, skim off any foam from the top.
Ladle the hot jam into sterilized jars, leaving about 1/4 inch of headspace.
Wipe the rims, place the lids on, and screw the bands on until they’re fingertip-tight.
How to Can Blackberry Jam Safely
Now comes the part that makes your jam pantry-ready: water bath canning.
Prep Your Water Bath Canner
Fill a large pot with enough water to cover your jars by at least one inch, and bring it to a rolling boil.
Make sure you have a rack at the bottom so the jars don’t touch the pot directly.
Process the Jars
Lower your filled jars into the boiling water using jar tongs, making sure they’re not touching each other.
Once the water returns to a full boil, start your timer.
Process half-pint and pint jars for 10 minutes, adjusting for altitude if you live above 1,000 feet.
Cool and Check the Seals
After processing, turn off the heat and let the jars sit in the hot water for five minutes before removing them.
Set them on a towel-lined counter to cool undisturbed for 12 to 24 hours.
You’ll know your jars are sealed when you press the center of the lid and it doesn’t pop back.
Any jars that didn’t seal should go straight into the fridge and be eaten within a few weeks.
So, How Do You Make and Can Blackberry Jam?
You make and can blackberry jam by cooking crushed berries with sugar and lemon juice until thick, filling sterilized jars, and processing them in a boiling water bath for 10 minutes.
It’s a straightforward process that rewards you with jars of rich, homemade jam you can enjoy all year long.
Once you know how to make and can blackberry jam, you’ll never look at store-bought jars the same way again.
Grab some berries, fire up that pot, and get canning.