What is it? The sweet potato and the yam can be so easily confused, but the two root vegetables come from two distinctive botanical families. The yam is native to Africa and Asia, and the sweet potato hails from Central and South America. The sweet potato's thin skin could be white, yellow, orange, red, or purple, while yams' skin comes only in white, pink, or a brownish-black.
Cut the two open and you'll notice a difference, too. Sweet potato flesh will be a vibrant orange or yellow. Compare that to yam flesh, which is paler, starchier, drier, and ranges in colour from purple to yellow to white to ivory.
Still, the two do look quite similar at first glance. That could be why African slaves cultivating sweet potatoes in North America began calling the vegetables by the name of the vegetable they had known back home - nyami. The name stuck, and still today if you ask for a yam in many grocery stores, you'll likely be handed a sweet potato.
What is it good for? Whether you choose the more common sweet potato or the harder-to-find yam, you'll dine on a nutritious, low-calorie vegetable. Of the two, sweet potatoes have more iron and are a better source of antioxidant vitamin A, but yams have more fibre. The two are about equal in heart-helper vitamin B6, but yams pack more of a punch than sweet potatoes for potassium, which is needed for proper heart, kidney, and muscle function.
What does it taste like? As its name reveals, the dominant flavour of a sweet potato is sweet. A yam, on the other hand, tastes earthier with barely a hint of sweetness. Depending on how you cook them, both yams and sweet potatoes can take on a soft, creamy texture that is easy to puree into soups or fillings for pies. Either can be baked and cut into cubes, which make great additions to on-the-go lunches. Roasting and steaming are two more common cooking options for both. The two vegetables share similar selection and storage guidelines as well: Choose firm yams or sweet potatoes - with no big cracks or bruises - and store unbagged in a cool, dark, well-ventilated place.