Add some ice to 4 glasses. Pour 2 to 3 tablespoons of the Cranberry Concord Syrup into the glasses and top with sparkling water. Stir gently and serve.
Cranberry Concord Syrup:
Combine the cranberries, grape jam, grape juice, sugar, and orange zest in a medium saucepan over medium-high heat.
Bring to a boil, then reduce the heat and simmer, stirring occasionally, until the cranberries are very soft and easily break apart when pushed with a wooden spoon, about 20 minutes.
Do not simmer too hard or the sauce may boil over. Let cool, then strain the syrup into a small pitcher.