Prep 30 mins
Cook 45 mins
Posted by request
- 4 cups crushed crushed fresh ripe, blackberries (8-9 pint baskets)
- 7 cups sugar
- 1⁄2 teaspoon unsalted butter
- 1 (3 ounce) package liquid pectin
- In an 8-quart pan, combine the blackberries, sugar, and butter.
- Over med-low heat, stirring constantly, heat the mixture until the sugar is completely dissolved.
- Increase heat to med-high and bring the mixture to a full rolling boil; stirring constantly.
- Stir in all the pectin; return mixture to a full rolling boil, stirring constantly.
- Boil, stirring constantly, for 1 minute.
- Remove pan from heat; skim off any foam.
- To prevent the jam from separating in the jars, allow the jam to cool 5 minutes before filling jars.
- Gently stir the jam every minute or so to distribute the fruit.
- Ladle the hot jam into hot jars, leaving ¼ inch headspace.
- Wipe the jar rims and threads with a clean, damp cloth.
- Cover with hot lids and apply screw rings.
- Process half-pint jars in a 200° water bath for 10 minutes, pint jars for 15 minutes.
- Tip: after cooking blackberry jam, the center white cores of the berries, to which the individual seeds were attached, will rise to the surface of the jam; as you stir the jam during the 5 minute standing period before ladling it into the jars, you may skim off as many of these cores as you can find—purely optional, but recommended if entering this jam in a competition.
- Tip: you may use frozen blackberries—you will need 2 to 3 (16 oz.) bags; do not rinse frozen berries before defrosting, and be sure to add all of the released juice to the pan, or the jam will be too thick.
- Tip: To reduce the quantity of seeds in the jam, sieve about ¼ of the berry pulp before measuring.