Introduction

Making blackberry jam without pectin is a rewarding way to capture the fresh, vibrant flavors of summer berries. This simple recipe relies on natural fruit and sugar to achieve a deliciously thick and spreadable jam that’s perfect for toast, desserts, or gifts.

A close-up view of a clear glass jar filled with thick, dark purple blackberry jam showing a slightly shiny, chunky texture on top, with a metal spoon lifting a generous scoop of the jam from the jar. To the right of the jar, there are four fresh blackberries scattered on a white marbled surface. The jam has visible small fruit pieces, giving it a rich and textured look, while the spoon reflects light subtly. The photo is sharp and focused on the jar and spoon, with the berries softly blurred in the background. photo taken with an iphone --ar 4:5 --v 7

Ingredients

6 cups mashed blackberries
4 cups granulated sugar
2 tablespoons lemon juice (optional)

Instructions

Step 1: Prepare the canning setup by washing and sterilizing 6 to 7 half-pint jars. Keep new lids warm in hot (not boiling) water, and have your boiling water bath canner ready. Keep everything hot until you’re ready to fill.
Step 2: Rinse and sort fresh blackberries, removing stems and debris. Use a potato masher to crush the berries in a large bowl or directly in the jam pot. Remember, it takes about 2 cups whole blackberries to make 1 cup mashed.
Step 3: Place the crushed blackberries in a large, deep pot. Stir in the sugar and lemon juice if using, mixing well to start dissolving the sugar before heating.
Step 4: Heat the mixture over medium-high heat, bringing it to a steady boil. Stir frequently to prevent scorching, and watch for foaming which is common with blackberry jam.
Step 5: Continue boiling and stirring until the mixture thickens and reaches gel stage, usually 20 to 30 minutes. Test doneness by checking if it wrinkles when cooled on a plate or using other jam-testing methods.
Step 6: Remove the pot from heat and skim off any foam that formed on top if desired.
Step 7: Ladle the hot jam into prepared jars, leaving ¼ inch of headspace. Wipe rims clean, then apply lids and screw bands on until fingertip tight.
Step 8: Process jars in a boiling water bath, fully submerging them with 1–2 inches of water above the lids. Process half-pint and pint jars for 10 minutes, or 15 minutes if above 6,000 feet elevation.
Step 9: After processing, remove jars and let them cool undisturbed for 12–24 hours. Check seals, label jars, and store in a cool, dark place for up to 18 months.

Tips & Variations

If you prefer a smoother jam, strain the mashed berries through a fine sieve before cooking to remove seeds.
Adding lemon juice not only brightens flavor but also helps with natural preservation and setting.
Use organic blackberries when possible for the best flavor and fewer pesticides.
For a different twist, stir in a teaspoon of vanilla extract or a few fresh mint leaves after cooking.

Storage

Store sealed jars of blackberry jam in a cool, dark place for up to 18 months. Once opened, keep jam refrigerated and use within 3 to 4 weeks. To reheat, simply warm gently on the stove or microwave for easier spreading.

How to Serve

A close-up view of a glass jar filled with dark purple blackberry jam, showing a shiny, slightly chunky texture with visible small bits of fruit. Over the jar, a silver spoon holds a scoop of the thick jam, with a glossy, sticky appearance. In the background on a white marbled surface, there are three whole blackberries, their textured surfaces slightly blurred. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Do I really need to use lemon juice in the jam?

Lemon juice is optional but recommended as it helps the jam set and preserves the bright color and flavor. It also balances the sweetness with a touch of acidity.

How can I tell when the jam has reached the right consistency?

You can test jam doneness by placing a spoonful on a chilled plate and letting it cool for a minute. If it wrinkles when nudged with a finger, it’s ready. Alternatively, use a thermometer; jam typically gels at 220°F (104°C).