The holiday feasting season — and all the family gatherings and parties that come with it — often means turkey, mashed potatoes and bright orange candied yams or, depending on who you ask, candied sweet potatoes.
While some may use sweet potato and yam interchangeably, botanically speaking, they are completely different vegetables. Even though both are starchy tubers, sweet potatoes and yams are not the same species or even in the same family.
Yams are in the family Dioscoreaceae, which contains hundreds of species of yams such as the Chinese yam and air potatoes, while sweet potatoes are in the family Convolvulaceae, which is the same family as morning glories.
The interchangeable use of sweet potato and yam to refer to an orange tuber is understandable. Often, sweet potatoes are labeled as yams in the produce section, so you may think you are buying a yam when it is actually a sweet potato.
According to the Library of Congress, sweet potatoes got labeled as yams when African slaves called soft-flesh sweet potatoes “yams” because they resembled the tuber that grew in West Africa.
Do yams and sweet potatoes look different on the outside?
The skin of a white or yellow yam from Africa is typically rough, fibrous and dark brown.
The sweet potatoes sold in most U.S. grocery stores have thin, smooth, reddish-brown skin, but there are some types that have dark red, tan or even purple skin.
Do yam and sweet potatoes look different when you cut them open?
The flesh of a yam you would find in the store in the U.S. is typically white or yellow, but there are some notable exceptions, such as the purple yam, or ube, that is popular in cuisine from the Philippines.
While sweet potatoes are typically thought of as having orange flesh, there are thousands of varieties grown worldwide that have flesh that ranges from purple to white to pink. Yes, there are both purple yams and purple sweet potatoes.
Do yams and sweet potatoes taste the same?
Yams are starchier than sweet potatoes and contain less sugar. White and yellow yams resemble a white potato when cooked.
Where do yams and sweet potatoes grow?
Sweet potatoes are grown in states such as North Carolina and California, but yams are mostly grown commercially in Africa and are typically only found in specialty stores in the U.S.
Other types of yams grow in tropical areas around the world, but some, such as the air potato, are bitter and toxic. The Chinese yam, or nagaimo in Japanese, grows in China and Japan and can be eaten raw.
Is a sweet potato just an orange potato?
A sweet potato is not just an orange potato. It is not even in the same plant family as other potatoes. White potatoes such as russet potatoes are in the family Solanaceae, which means they are more closely related to tomatoes than sweet potatoes.
According to “The Oxford Encyclopedia of Food and Drink in America,” sweet potatoes were likely domesticated around 8000 BCE in South and Central America. Spanish colonizers came across sweet potatoes in the Caribbean and shipped them to Europe. They ended up giving similar names to both white potatoes from South America and sweet potatoes, hence the confusion.
In the U.S., most sweet potatoes are grown in North Carolina and there, the nonprofit corporation of the sweet potato growers calls them “sweetpotatoes” as one word instead of two to show they are not just another variety of potato.