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 mixture through a fine mesh sieve or cheesecloth into a pitcher, pressing firmly to extract all liquid while removing skins and pulp.
04 - Taste the agua fresca and add additional sugar or lime juice as desired to achieve preferred sweetness level.
05 - Refrigerate until thoroughly chilled or serve immediately over ice cubes in filled glasses.
06 - Decorate glasses with fresh mint sprigs or additional whole grapes as desired.