Have you ever wondered about what the difference is between sweet potatoes and yams? Sweet potatoes are also called ‘yams’ — however these tuberous root vegetables are actually from two very different plants. Sweet potatoes are related to morning glories and true yams are related to palms and grasses. When you buy a ‘yam’ at the supermarket, you are really buying a sweet potato. True yams are imported, starchy and dry in texture, and not grown in the U.S. And guess what — sweet potatoes are not related to potatoes! Confusing — yes. But the term ‘yam’ has stuck for sweet potatoes sold in the U.S. and it is used interchangeably.
North Carolina is the largest U.S. producer of yams followed closely by California. Sweet potato varieties are classified as either ‘firm’ or ‘soft.’ Firm sweet potatoes are golden skinned with a pale interior and remain firm and slightly waxy when cooked. It is the ‘soft’ orange-fleshed varieties with purple or coppery skins that are often labeled as yams in the United States.
Also, keep this in mind — if you are making a Caribbean or Indian dish and the recipe calls for yams, be sure to visit an ethnic market for that ingredient. (Here’s a photo of what true yams look like.) Substituting American ‘yams’ or sweet potatoes may not work. A true yam has a rough, scaly, brown exterior and a creamy color flesh. Its flesh is also much firmer, even after cooking. You might be able to get away with using the firm, golden skinned sweet potato — but most likely the fluffy soft texture of the orange-fleshed sweet potato we call a ‘yam’ in the U.S. will not work.
Although generallly available year round, peak season for sweet potatoes is from October through December.
Not only delicious, one sweet potato packs twice the recommended daily allowance of vitamin A, with loads of vitamin C, calcium, fiber, along with a healthy dose of vitamins B and B6, and only 141 nutrient-dense calories.
Store sweet potatoes in a cool dry place for up to four weeks.