See Below

Select fully ripened fruits and rinse them quickly under cold water and
then drain thoroughly. Do not soak the fruit in water. Do not double the
recipes. Do not substitute ingredients. Do not reduce the amount of sugar
or increase the amount of fruit used. An exact balance of fruit, sugar, and
pectin is needed for jelling to occur. For no cook jams, mash the fruit
with a potato masher. For cooked jams, process the fruit in a food
processor using quick on and off pulses until finely chopped. For
preserves, until coarsely chopped. Do NOT puree.

NOTE:

A rolling boil is a boil that cannot be stirred down.