The sweet tubers are small, often about the size of a thumb, are pink-orange in colour and have a slightly shiny and ribbed surface. Yams are eaten cooked and in this form the carotenoids are more available. Boiling or steaming minimises their oxalate levels. Serve whole or mashed. Use sliced in stir fries. The natural sweetness of yams is enhanced with ginger, orange or sweet and sour sauces.