Not to be confused with the poison sumac that resembles poison ivy (with loose, drooping clusters of greenish-white berries), staghorn sumac is a shrub that sports tight, upright clusters of red fruit beginning in mid-summer. To tell if the berries are ripe, lick your finger, insert it in the berry cluster and taste. If the flavor is pleasantly tart, they’re ready. Pick the berry clusters, immerse in a bowl of water for several minutes, and rub the berries to impart their red color, tart flavor, and vitamin C content into the water, then strain and serve sweetened or unsweetened, hot or cold. Cohen prefers to serve his sweetened and cold, like pink lemonade.