Boil 1 cup of sugar with 1 cup of water for 3 minutes. Set aside to cool. In a large pitcher, pour a cold bottle of white wine and Calvados to taste. Add in slices of Granny Smith apples and halved green grapes until it's quite full of fruit. Allow to sit in the fridge, covered, for a few hours. Add a bottle of seltzer and the cooled simple syrup to taste. Stir, and serve cold.
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