Liquid pectin can be substituted for powdered pectin in all of these recipes, with no difference in results. Simply reverse the order in which the pectin and sugar are added.
Be careful not to crush the berries too much; you want the jam to have some texture.
Black and Red Raspberry Jam: Substitute any proportions of black and red raspberries.
Red Raspberry Jam: Substitute red raspberries and increase the sugar to 6 1/2 cups.
Peach Blueberry Jam: Substitute 2 cups of peeled, pitted, and chopped peaches for 2 cups of the blueberries.
Sour Cherry Jam: Substitute stemmed and pitted sour cherries, increase the sugar to 5 cups, and omit the lemon juice.
Gooseberry Jam: Substitute stemmed, crushed (but not pureed) gooseberries.