|Mashed blackberries||3 Cup (48 tbs), or sieved|
|Sugar||5 1⁄2 Cup (88 tbs)|
|Powdered fruit pectin||1 3⁄4 Ounce (1 box)|
|Water||1 Cup (16 tbs)|
Mix the berries and sugar in a bowl; let stand 20 minutes, stirring occasionally.
Blend the pectin and water in a large saucepan; bring to boiling and boil rapidly 1 minute, stirring constantly.
Remove from heat; add the berry-sugar mixture and stir about 2 minutes.
Ladle into clean hot jars, cover, and let stand 24 to 48 hours, or until the jam is "set".
Store, tightly covered, in freezer.
(Jam will keep several weeks in refrigerator.)