My seven year old daughter is becoming the family berry picker. Everyday she goes out to the patch of black raspberries to check and pick. So far, she is only getting a couple cups at a time, but soon the blackberries will be ripe and picking will become a family job.
3 pints blackberries (6 cups)
5 1/4 C sugar
1 box Sure-Jell
Mash berries with a potato masher one cup at a time. Add sugar to crushed fruit. Stir and allow to sit for ten minutes. Put pectin and 3/4 C water into a sauce pan. Bring to a boil stirring constantly. Boil for one minute. Add mixture to berries and stir for about three minutes until sugar is dissolved. Pour into containers. Allow to sit at room temperature for 24 hours. Keeps in the refrigerator for about three weeks or up to a year in the freezer.
I don't have many freezer boxes. I freeze most things in bags. Trust me, bags are not the way to freeze freezer jam. What a mess! Instead I used recycled food containers like cottage cheese containers. Works wonderfully. Just be sure to label your container!