Lightly rinse frozen berries under cold running water; drain well. Transfer berries to a 5-6 quart nonreactive kettle or Dutch oven, such as enamel or stainless steel. Add the 3 cups water. Bring to a boil; reduce heat to medium-low. Cover and simmer for 15 minutes. Slightly mash fruit against inside of kettle using the back of a spoon. Strain the juice, discard berries. Pour 4 cups of the juice in the nonreactive kettle or Dutch oven. Add lemon juice and pectin, and stir. Bring to a boil, add sugar, stir, and bring to a full, rolling boil. Boil exactly 2 minutes. Skim and pour into clean, hot jars. Seal.