Sweet Potatoes and Yams 101
Yams and sweet potatoes are botanically unrelated. Yams are tubers from Africa or Asia; sweet potatoes are native to the Caribbean or Latin America.
Choose yams and sweet potatoes with tight, unwrinkled, firm skins and no blemishes. Avoid potatoes with bruises that cannot be cut away, as they impact flavor and nutrition. Prime season is October to January. Sweet potatoes are available fresh and canned (often labeled erroneously as yams).
Although stores may call products “garnet yams” or yams, nearly all “yams” sold in the US are actually sweet potatoes. The range of color of the flesh is from white to yellow to red, purple or orange red. Most US varieties are soft which cook up soft and moist. True yams are starchier and drier and have a rough skin; sweet potatoes have smooth skins.
Cook and use as you would any potato: bake, stir fry, or steam and serve whole, in pieces or slices, mashed or however you desire. Sweet potatoes can be eaten raw, but never true yams.
Yams and sweet potatoes can be stored in a dry cool (55 F) cupboard up to 3-4 weeks. Do not refrigerate. Cooked potatoes may be refrigerated in a covered container for 4-5 days. May be frozen in airtight container; leave ½ inch and store at 0 F for 10-12 months.
Sweet potatoes are high in vitamins A and C, calcium, iron and fiber. Yams pale in comparison, but are still a good source of potassium, manganese, vitamin C and fiber.
If seeking true yams, check Latin American or Caribbean markets where they are sometimes called boniato and have brown or black skin, similar to tree bark and off white, purple or red flesh depending on the variety. Has higher moisture content and more natural sugar than the sweet potato. Raw yams are toxic.