- 1/2 pound Concord grapes (about 44 grapes)
- 1/2 cup vodka
- 1/4 cup superfine sugar
- 1/4 cup fresh lime juice (from about 3 limes)
- 1 cup ice
- Reserve 4 grapes for garnish. Crush remaining grapes in a shaker with a wooden spoon to release juice. Strain through a fine-mesh strainer; discard solids. (You should have about 1/2 cup juice.) Rinse out shaker. Stir vodka and sugar in a bowl until sugar dissolves, about 3 minutes. Combine grape juice, vodka mixture, lime juice and ice in shaker. Shake well and strain into 4 martini glasses. Garnish each with 1 grape and serve.