There is some confusion in the kitchen about yams and sweet potatoes. What you have likely been calling a yam isn't a yam at all! Grocery store labels for the two tubers aren't always correct either. There is a big difference between the two veggies. It's best to clear up the confusion before you reach for the candied yams and sweet potato casserole at the Thanksgiving table this fall.
While both sweet potatoes and yams are root vegetables that come from a flowering plant, they are actually unrelated and have very different origins and uses. Yams are not a sweet potato, and sweet potatoes are not a type of yam. Grocery stores and recipes often use the names interchangeably, creating lots of confusion over which is which.
A true yam is native to Asia and Africa, where 90% of the world's yam crop is grown. Yams are cylindrical in shape with a black-brown, bark-like skin and white, purple, or reddish flesh. Yams are starchier and drier when compared with sweet potatoes. Yams can be very difficult to find in a typical grocery store. If you want to find some, your best chance is to check an international or specialty market. Shown below is a purple yam. Note the rough skin and firm flesh.
There are many varieties of sweet potatoes. Skin color for sweet potatoes ranges from light yellow and white to darker red, purple or brown. Sweet potatoes have an elongated shape with tapered, pointed ends. Many varieties of sweet potatoes are grown in the United States. Two popular varieties include firm sweet potatoes, which have a light, golden yellow skin and white flesh, and soft sweet potatoes, which have a red, coppery skin and orange flesh. The latter of these varieties are often called "yams" to create more distinction between the two varieties, furthering the confusion between yams and sweet potatoes. Below is the soft variety of sweet potato, often labeled as a "yam" in the grocery store.
The firm, white sweet potatoes remain relatively firm and a little waxy when cooked. Soft, orange-fleshed sweet potatoes, or "yams," become moist, creamy, and almost fluffy when cooked.
Know that when you purchase "yams" in your everyday grocery store, you are most likely selecting the soft variety of sweet potato.
If you are looking for great sweet potato recipes, here are 34 sweet potato recipes you should be making, but aren't including sweet potato casserole, pie, and potato skins!
For more detailed instruction on how to cook with true yams, check out this guide on preparing and using yams in recipes!