Blackberry Jam Recipe Without Pectin

4.40 from 868 votes

Blackberry jam is a classic preserve made with just berries, sugar, and time. This no-pectin version highlights the bold flavor of summer blackberries in a thick, spreadable jam that's perfect on toast or stirred into yogurt.

Prep Time5

Cook Time25

Additional Time10

Total Time40

Course: Canning

Cuisine: American

Servings: servings, makes 5 to 6 half pint (8oz) jars

Author: Ashley Adamant

Equipment

Water Bath Canner

Ingredients

6 cups mashed blackberries see note
4 cups granulated sugar
2 tablespoons lemon juice optional, see notes

Instructions

Prepare canning setup: Wash and sterilize 5-6 half-pint jars. Place lids in hot (not boiling) water. Prepare your boiling water bath canner and keep everything hot until ready to fill.
Crush the berries: Rinse and sort fresh blackberries, removing any stems or debris. Use a potato masher to crush them in a large bowl or directly in the jam pot. Generally, 2 cups whole fruit yields about 1 cup mashed.
Combine fruit and sugar: Place crushed blackberries in a large, deep jam pot. Stir in sugar and optional lemon juice. Mix thoroughly to help sugar dissolve before heating.
Bring to a boil: Turn heat to medium-high and bring to a steady boil, stirring frequently to prevent scorching. Blackberry jam foams heavily, so stay nearby and stir often.
Cook to gel stage: Continue boiling, stirring constantly, until jam thickens and reaches gel stage. This typically takes 20-30 minutes. Test using the freezer plate test (jam wrinkles when pushed) or an instant-read thermometer (220°F at sea level).
Remove from heat and skim foam: Once gel stage is reached, remove pot from heat. Skim off any remaining foam if desired.
Ladle into jars: Carefully ladle hot jam into prepared jars, leaving ¼ inch headspace. Wipe rims with a clean damp cloth, apply lids, and tighten bands to fingertip tight.
Process in water bath canner: Place jars in boiling water bath canner, ensuring they're fully submerged with 1-2 inches of water above lids. Process for 10 minutes (15 minutes above 6,000 feet).
Cool and store: Remove jars and let sit undisturbed for 12-24 hours. Check seals, label, and store in a cool, dark place for up to 18 months.

Notes

Blackberry Measurements: Generally, 2 cups whole berries equals 1 cup mashed fruit. One cup mashed is about ½ pound, so you'll need about 3 lbs whole fruit (12 cups as purchased) for this recipe.

Sugar Options:

Recommended (4 cups): Balanced sweetness with good fruit flavor
Low Sugar (2-3 cups): More tart and fruit-forward; may take longer to reach gel stage
Traditional High Sugar (6 cups): Very sweet with firm set; old-fashioned style

Lemon Juice (Optional): Blackberries are naturally high in acid, so lemon juice isn't required for safety. However, 1-2 tablespoons brightens flavor and balances sweeter cultivated berries. Skip if your berries are already tart. Fresh lemon juice is fine since blackberries are acidic enough for safe canning.

Testing for Gel Stage:

Freezer plate test: Spoon jam onto a cold plate, wait 30 seconds, push your finger through. If it wrinkles and holds a line, it's done.
Temperature test: Jam sets at 220°F at sea level. Subtract 2°F for every 1,000 feet of elevation.
Sheeting test: Dip a spoon in jam and hold sideways. If jam falls in a sheet (not droplets), it's ready.

Foam Management: Blackberry jam foams heavily. Stir constantly to manage. You can add ¼ teaspoon butter during cooking to reduce foaming (safe for canning but may affect long-term flavor). Skim remaining foam before jarring.

Batch Size: This recipe can be doubled but don't increase beyond that. Larger batches don't cook evenly and may not set properly.

Storage: Sealed jars keep 12-18 months in the pantry. Once opened, refrigerate and use within 2-3 weeks. Low sugar jams spoil faster once opened than high sugar versions.

Removing Seeds: For seedless jam, run cooked berries through a fine mesh strainer or food mill before adding sugar. For completely smooth seedless spread, make blackberry jelly instead by straining juice through a jelly bag.

Nutrition