What's the Difference Between Yams and Sweet Potatoes?

Spoiler: They're not the same vegetable.

It's easy to sit before a fall produce stand or Thanksgiving spread and assume sweet potatoes are synonymous with yams, but the reality is a little more complicated. That's because sweet potatoes and yams are in fact very different vegetables that we've come to refer to interchangeably for a number of reasons over the years. While a dish may arrive at your table calling itself "candied yams," it may well have been made with sweet potatoes. And, a sweet potato may well be labeled "yams" at your local supermarket. In other words, it's very easy to get confused.

So, here's a quick explainer on yams vs. sweet potatoes that should help you distinguish them from one another. 

sweet potato
This is a sweet potato | Shutterstock/mama_mia

What is a sweet potato?

The most widely available sweet potatoes in the United States include cultivars like Beauregard, garnet, and jewel. They tend to have copper skins, orange flesh, and tapered ends. Most have juicy textures, making them good candidates for baking.

However, there are lots of different soft and firm varieties of sweet potatoes. They can have varying textures, consistencies, and interior and exterior colors. Okinawa sweet potatoes, also known as beni-mo, have dusty, gray-tinted skins and vibrant purple interiors. There are also white- and yellow-fleshed sweet potatoes like Boniato and satsuma-imo, which might also be sold as Cuban and Japanese sweet potatoes, respectively. 

Confusingly, many of these varieties may be called "yams" in grocery stores, although the US Department of Agriculture does require them to accompany such a label with "sweet potato" somewhere.

Fun fact: sweet potatoes are in the same family as morning glory flowers.

This is what yams look like | Shutterstock/Aku Alip

What is a yam? 

A true yam has rough, bark-like skin that tends to be a darker brown than most sweet potatoes, and usually have a pale, creamy-colored interior. There are also yellow- and purple-fleshed varieties, though they are less commonly found in the US.

Yams have a starchy, dry texture that is somewhat similar to yuca, and makes them suited to baking, roasting, and stewing. Yams can also vary greatly in size, from handheld tubers to 130-pound vegetables. 

Some historians and linguists believe the English word yam derived from nyam, nyami, or nyambi, which are terms in African dialects that mean "to eat" and "to taste." Yams arrived in North America during the Transatlantic Slave Trade, and enslaved Africans created an array of dishes using both West African yams and orange-hued sweet potatoes during the antebellum period that were and remain integral to US foodways. 

Fun fact: yams are closely related to lilies.

So, what is a yam vs a sweet potato?

Sweet potatoes are native to the Americas and are members of the morning glory family, Ipomoea. They tend to have softer, russet-hued skins and creamy interiors. Yams are of a different genus (Dioscorea) and originally hail from Asia or Africa. They typically have rough brown exteriors and starchy white interiors, and can grow to be much larger than most sweet potatoes.

In case you're hungry for some Thanksgiving sweet potato casserole now, here's our recipe.

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Joe McGauley is a senior writer for Thrillist. Follow him @jwmcgauley.