Seedless Blackberry Jam

5 from 2 votes

This seedless blackberry jam is smooth, glossy, and packed with deep berry flavor—no seeds in sight. Made the old-fashioned way without added pectin, it’s perfect for topping yogurt, layering in desserts, or spreading on soft pastries.

Prep Time30

Cook Time20

Canning Time10

Total Time1

Course: Jam

Cuisine: American

Keyword: blackberry canning recipes, no pectin

Servings: servings, Makes about 4 to 5 (8 oz) Jars

Equipment

Water Bath Canner

Ingredients

16 cups blackberries see notes
4 cups sugar
2 tbsp lemon juice optional, see notes

Instructions

Prepare your canning setup: Wash and sterilize 6 to 7 half-pint jars. Place new lids in hot water (not boiling), and prepare your water bath canner. Keep everything hot until ready to fill.
Cook the berries to loosen seeds: Combine the mashed blackberries and water in a deep saucepan or jam pot. Bring to a gentle boil and simmer for about 5 minutes, mashing with a potato masher as they cook. The fruit should break down completely and release its juice.
Strain out the seeds: Working in batches, press the softened berries through a fine mesh strainer, chinois, or food mill fitted with a berry screen. You should end up with approximately 6 cups of seedless blackberry pulp. A little more or less is fine—just be sure to adjust the sugar (see notes).
Measure and add sugar: Return the seedless pulp to a clean jam pot. Stir in 4 cups granulated sugar and optional lemon juice. Mix well to dissolve some of the sugar before heating.
Bring to a boil: Turn the heat to medium-high and bring the mixture to a rolling boil, stirring frequently. Use a deep pot, as seedless blackberry jam foams quite a bit.
Cook to gel stage: Boil the jam, stirring constantly, for about 15–20 minutes or until it reaches gel stage. Test for doneness using the plate test, thermometer method, or sheeting test (see notes).
Remove from heat and skim foam: Once gel stage is reached, take the pot off the heat. Skim off any foam from the surface if desired.
Ladle into jars: Carefully ladle the hot jam into prepared jars, leaving ¼ inch headspace. Wipe rims clean, apply lids, and screw on bands until fingertip tight.
Process in a water bath canner: Submerge jars in boiling water with at least 1–2 inches above the lids. Process pints and half pints for 10 minutes, or 15 minutes about 6,000 feet in elevation.
Cool and store: Remove jars and let them sit undisturbed for 12–24 hours. Check seals, label, and store in a cool, dark place for up to 18 months. Refrigerate after opening and use within 2–3 weeks.

Notes

Blackberry Measurements: Start with about 4 lbs (or 16 cups) whole blackberries. After mashing and cooking, you’ll have ~8 cups mashed fruit. Once strained, expect about 6 cups of seedless pulp.

Sugar Ratio: This recipe uses a 3:2 fruit-to-sugar ratio by volume. If you get slightly more or less pulp, adjust the sugar accordingly. (Example: 5 cups pulp = ~3⅓ cups sugar.)

Lemon Juice (Optional): Blackberries are high in natural acid, so lemon juice isn’t needed for safety. However, a splash (1 to 2 tablespoons) of fresh lemon juice can enhance flavor and help with gelling—especially if your berries are sweet cultivated types.

Foam Control: Seedless blackberry jam tends to foam during cooking. If it bothers you, stir in ¼ teaspoon of butter during cooking or skim the foam off at the end. Both methods are safe for canning.

Yield: You should get around 4 to 5 half-pint jars, depending on how long you cook the jam and how juicy your berries are. A longer cook time yields a thicker jam but slightly less volume.

Freezer Option: If you’d prefer not to water bath can, pour cooled jam into straight-sided freezer-safe jars, leaving ½ inch headspace. Freeze for up to a year.

Gel Stage Testing Methods

Plate Test: Freeze a plate and spoon. Place a spoonful of jam on the cold plate and wait 30 seconds. Run your finger through it—if it wrinkles and holds a line, it’s done.

Thermometer Test: Jam gels at 220°F at sea level. Subtract 2°F per 1,000 ft of elevation.

Sheeting Test: Dip a spoon into the jam and turn it sideways. If it falls in a sheet or slow blob rather than droplets, it’s likely done.

Altitude Adjustments

If canning, both pints and half pints are canned in a waterbath canner for 10 minutes. If you’re above 6,000 feet in elevation, be sure to increase the canning time to 15 minutes. Don’t can in jars larger than pints.

Nutrition