In a large sauce pan add grapes, 1 cup water, 1 cup of sugar and lemon zest.
Simmer over medium heat, mashing grapes as they soften.
Once all the grapes have been mashed, let the mixture simmer gently for an additional 10-15 minutes so that the grape skins release more of its color.
Remove from heat and strain, discarding the solids.
Add grape mixture to a pitcher.
Stir in lemon juice and remaining cold water and sugar.
Taste and adjust the water and sugar to your liking.
Refrigerate until chilled. (This tastes bolder the next day)
Serve over ice and enjoy!