Grapes, Unripe

These grapes, used as a souring agent in many Iranian dishes, are sold at Persian groceries in various forms: fresh in season, whole frozen, and canned; as unripe grape juice (ab-ghureh), also known as verjuice; and as powdered unripe grapes (gard-e ghureh). Although the taste will not be quite the same, you can substitute fresh lime juice for them in recipes: Allow 4 tablespoons lime juice per 1½ cups unripe grapes, 1 cup juice, or 1 tablespoon powder. See How To section.