Prepare Pomona's "Calcium Water" following the instructions in the box.

Sterilize 6 -.5Pint Canning Jars or the equivalent according to preference.

Whisk the sugar and pectin powder together in a bowl and set aside.

Place the mashed berries in a pot on the stove and add lime zest, lime juice, and "calcium water."

Bring the berry pot to a boil.

Add the sugar-pectin mixture to the pot.

Stir vigorously for 1-2 minutes to dissolve the pectin.

Return to the jam to a boil and then remove it from the heat.

Ladle the hot jam into sterilized jars, leaving .25-in head space.

Process 10 minutes in a boiling water canner.

Note that Pomona's pectin takes longer to set than other pectins. The jam might not really appear set in the jar for several days.