Blackberry Jam

There’s something almost magical about turning a pile of fresh blackberries into a jar of glossy, deep-purple jam. I still remember picking blackberries as a kid, fingers stained dark and arms scratched from the brambles, racing home to see what my grandmother would make with them.

This recipe brings all of that back — it’s simple, honest, and the kind of thing you’ll want to make every single season. No fancy equipment, no pectin packets, just real fruit and a little patience. Whether you spread it on toast, swirl it into yogurt, or sneak spoonfuls straight from the jar, this jam delivers every single time.

Why We Love This Blackberry Jam Recipe

This jam earns a permanent spot in our fridge for all the right reasons — here’s exactly why we keep coming back to it.

• Only 6 ingredients — Everything is likely already sitting in your pantry or fridge
• Done in under an hour — From stovetop to fridge, it’s a surprisingly quick process
• No pectin needed — Cornstarch does the thickening work naturally and beautifully
• Bright, balanced flavor — A splash of lemon juice at the end lifts the whole thing
• Incredibly versatile — Works on toast, biscuits, pancakes, cheese boards, and more
• Fridge-friendly — Keeps well chilled and tastes even better the next day
• Beginner-friendly — No canning experience or special tools required

Ingredients

• 4 cups blackberries
• 1 cup white sugar
• 2 tablespoons cornstarch
• ¼ teaspoon ground cinnamon
• ¼ teaspoon ground allspice
• ½ teaspoon lemon juice

Step-By-Step Directions

Step 1: Gather all of the ingredients so everything is ready before you begin.

Step 2: Add the blackberries to a saucepan and mash them well using a potato masher until they release plenty of juice.

Step 3: Stir the sugar into the mashed blackberries until the juices begin to flow. In a small bowl, combine 1 tablespoon of the blackberry juice with the cornstarch until smooth, then stir the mixture back into the saucepan.

Step 4: Bring the blackberry mixture to a gentle boil. Cook for about 15 minutes, stirring frequently, until the jam thickens to your desired consistency.

Step 5: Mix in the cinnamon and allspice, then remove the saucepan from the heat. Let the jam cool for 30 to 45 minutes.

Step 6: Spoon the cooled jam into a bowl, cover, and refrigerate until thoroughly chilled. Stir in the lemon juice just before serving for the freshest flavor.

Tips for the Best Results

Use ripe, in-season berries — The riper the blackberry, the deeper and more complex your jam will taste. Overripe fruit works great here too

Low and steady wins — If your heat is too high, the jam can scorch quickly. Medium heat with frequent stirring is the sweet spot

Adjust the spices to your taste — Love warm spice? Add a pinch more cinnamon. Want it simpler? Leave out the allspice entirely

Always add lemon juice last — Adding it during cooking dulls the brightness; stirring it in cold keeps it lively and fresh

Test the set on a cold plate — Drop a small spoonful on a chilled plate. If it wrinkles when you push it, your jam is ready

Use a clean, dry jar — Even for a fridge jam (not shelf-stable canning), starting with a clean container keeps things fresh longer

Storage

This jam is made as a refrigerator jam, not a shelf-stable canned product. Here’s what you need to know:

• Refrigerator: Keeps well in a sealed jar or airtight container for up to 2–3 weeks
• Freezer: Pour cooled jam into a freezer-safe container, leaving a little headspace for expansion. It will keep for up to 6 months — just thaw overnight in the fridge when ready to use
• Best container: Glass jars with tight-fitting lids work best for maintaining flavor and freshness
• Signs it’s turned: If you notice any mold, an off smell, or an unusual texture, discard and make a fresh batch — it only takes 45 minutes anyway!

Print Recipe

Blackberry Jam

There's something almost magical about turning a pile of fresh blackberries into a jar of glossy, deep-purple jam. I still remember picking blackberries as a kid, fingers stained dark and arms scratched from the brambles, racing home to see what my grandmother would make with them.

Prep Time10 minutes mins

Cook Time15 minutes mins

Total Time25 minutes mins

Servings: 8

Instructions

• Gather all your ingredients and set them out before you start. Having everything within reach makes the whole process smoother.
• Add the blackberries to a medium saucepan and use a potato masher to crush them down into a rough, juicy mash.
• Stir the sugar into the mashed blackberries and let it sit until the juices start releasing. Scoop out 1 tablespoon of juice and whisk it with the cornstarch in a small bowl until smooth. Stir the slurry back into the saucepan.
• Bring the mixture to a boil over medium heat, stirring frequently, until the jam thickens and coats the back of a spoon — about 15 minutes.
• Remove from heat and stir in the ground cinnamon and allspice. Allow the jam to cool in the pan for 30 to 45 minutes.
• Spoon the cooled jam into a jar or bowl, cover, and refrigerate until fully chilled. Stir in the lemon juice just before serving.

Notes

 

• This is a refrigerator jam — not shelf-stable. Store in a sealed jar in the fridge for up to 2–3 weeks, or freeze for up to 6 months.
• Add lemon juice after chilling, not during cooking, to keep the brightness fresh.
• Test the set by dropping a small spoonful on a cold plate — if it wrinkles when pushed, it’s ready.

 

Nutrition Facts:

 

• Calories: 34
• Total Carbohydrate: 8g
• Dietary Fiber: 1g
• Total Sugars: 7g
• Protein: 0g
• Total Fat: 0g
• Saturated Fat: 0g
• Cholesterol: 0mg
• Vitamin C: 4mg
• Sodium: 0mg
• Calcium: 6mg
• Iron: 0mg
• Potassium: 30mg

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