01 - Combine grapes, water, sugar, and lime juice in a blender. Process on high speed until completely smooth and frothy.
02 - Pour the blended mixture through a fine mesh sieve or cheesecloth into a pitcher, pressing firmly to extract all liquid and remove skins and pulp.
03 - Taste the agua fresca and add additional sugar if needed, stirring until fully dissolved.
04 - Pour over ice cubes in glasses. Garnish with fresh mint leaves or additional whole grapes if desired. Serve chilled.