Puree whole grapes until completely blended.
Measure out 12 liquid cups (adjust with grape juice if necessary) and pour into heavy bottomed stock pot.
In a separate bowl, combine sugar and pectin thoroughly. Set aside.
Add lemon juice, ginger and calcium water to grape puree and bring to low boil over medium heat, stirring frequently.
Once the mixture boils, slowly add in sugar/pectin mixture. Continue to cook for 3-5 minutes, stirring to ensure that all sugar/pectin is thoroughly dissolved. The hot jam should coat the back of a spoon and will thicken upon cooling.
Ladle into sterilized half pints jars, leaving a 1/4" head space. Wipe rims of jars and screw on prepared lids and rings finger tight.
Process in water bath canner for 10 minutes.
After processing, remove from canner and allow to cool, undisturbed for 12 hours. Check for seal and loosen or remove ring for storage.