Mash berries with a potato masher. Stir in sugar. Add hot pectin water and calcium water*. Stir well. If jell does not begin to appear, add a little more.
Freeze immediately in pint or half-pint containers. Straight-sided glass canning jars seem to freeze without bursting if the top 1/2 inch is left empty for expanding jam.
We made this with early season berries. Late season berries may require less added sugar.
Most stone fruits and other berries benefit from 2-4 Tbsp fresh lemon juice.
* We used Pomona's Universal Pectin, which claims, "Jells with any amount of sweetner."