A tall, brawny Irish American walks into your office, puts a crystal goblet on the desk, and pours out a serving of a deep-purple nectar. "This stuff used to be illegal," he says in a gravelly voice. "We're the guys who got the law changed. Twice the antioxidants of blueberries, four times the vitamin C of orange juice, as much potassium as bananas … Try it." Something like grape juice but heavier, not as sweet; tart but not as much as cranberry; dry, strong, and complex, like a good red wine. M