Black Spanish Radish or Erfurter Radish. Edible root has a tough black skin and white flesh. Like other radishes, black radish has a sharp flavour - its unique flavour characteristics can bring depth to salads, pickles and even healthy Winter soup. Particularly rich in vitamin C, a powerful antioxidant, contains B vitamins, potassium, magnesium, as well as dietary fiber and enzymes beneficial for digestion.