01 - Place grapes, water, sugar, and lime juice in a blender container.
02 - Blend on high speed until completely smooth and frothy, approximately 1-2 minutes.
03 - Pour the blended mixture through a fine mesh sieve or cheesecloth into a pitcher, pressing with a spoon to extract all liquid and remove skins and pulp.
04 - Taste the agua fresca and add additional sugar or lime juice as needed to achieve desired sweetness and balance.
05 - Refrigerate until thoroughly chilled or serve immediately over ice cubes in tall glasses.
06 - Garnish each serving with fresh mint leaves or additional grapes if desired.