What is the Difference Between Yams and Sweet Potatoes?

Yams and Sweet Potatoes

The changing of the seasons from summer to fall can mean a lot of things: a new school year, crisper weather, and the beginning of the holidays. If you’re a true lover of the holidays, you go all out for all of them: Halloween, Thanksgiving, Christmas or Hanukkah, and New Year’s. For foodies and cooks, the advent of autumn also means it’s finally the season for all our favorite orange vegetables: pumpkins, squash, yams, and sweet potatoes.

But did you know you might actually have been confusing some of those vegetables all these years? While it’s fairly easy to tell a pumpkin apart from squash and vice versa (hint: a raw, whole pumpkin looks like a jack-o-lantern without a face), a lot of people have been confusing yams with sweet potatoes all their lives. Our supermarkets may be to blame: lots of them label the two interchangeably. And most lay people would be hard-pressed to tell the difference. The confusion is so wide and deep that many of our most cherished holiday dishes are actually not what we think they are. Candied yams? They’re delicious, but what you’ve been having all these years is probably sweet potatoes topped with brown sugar and marshmallows!

Read on to learn the difference between yams and sweet potatoes and how you can tell them apart before you prepare your next fall meal.

The Difference Between Yams and Sweet Potatoes

Yams and sweet potatoes are both tuberous root vegetables that can have a pinkish orange inside and dark orange-hued skin. But while they may sometimes look similar, they are different vegetables. In fact, they have completely different botanical roots (no pun intended). Yams are the tuber vegetables that come from the Dioscorea batatas plant, which belong to a family of plants that includes grasses and lilies. Sweet potatoes are part of the genus Ipomoea plant, which belongs to the morning glory family. That may not mean much to the non-agriculture expert, but suffice it to say that the two vegetables, however similar they may look, have no relation with one another whatsoever.

Due to their different roots, yams and sweet potatoes are popular in different parts of the world. The yam grows better in hotter, tropical climates, and is eaten regularly throughout the Caribbean and Latin America, where it’s known as simply “batatas” after the scientific plant name of its plant. Sweet potatoes are more popular in the United States and throughout Europe, although they are also eaten in Central America and other parts of the world.

Yams and Sweet Potatoes

How to Tell a Yam from a Sweet Potato

Yams usually have brownish skin with pale, cream-colored flesh on the inside. Sweet potatoes, on the other hand, are usually reddish brown on the outside and orange on the inside. Yams are also drier and starchier than sweet potatoes. That said, both vegetables have different varieties: there are some yams with dark, purple-hued skin that can easily be confused for sweet potatoes. Likewise, there are some varieties of sweet potatoes with pale flesh.

So how can you tell them apart at the grocery store? The most surefire way to tell the difference is to pay careful attention to the labeling. The U.S. Department of Agriculture requires that sweet potatoes include the words “sweet potato” somewhere on the label. What often ends up happening is that grocery stores will misleadingly label sweet potatoes “yams” but include “sweet potato” somewhere on the label or fine print. If the vegetable is labeled simply as a “yam,” it’s probably a true yam.

It’s also helpful to know that true yams can be hard to find in the U.S. outside of international or specialty supermarkets. So more often than not, what you’re buying is a sweet potato.

Why Are Yams and Sweet Potatoes So Often Confused for One Another?

The reason for the confusion has to do with the fact that there are two types of sweet potatoes, firm, sweet potatoes and soft sweet potatoes. Firm, sweet potatoes have golden skin and pale flesh. They look a bit like regular potatoes, although they are often less round. Soft sweet potatoes more closely resemble what you normally think of as a sweet potato or a yam: purple or dark orange on the outside, with soft orange flesh on the inside. Firm, sweet potatoes were first to arrive in the U.S. market. When the softer variety arrived later, many stores started calling them “yams” in order to differentiate them from their browner, starchier earlier varieties.

Yams and Sweet Potatoes

So now you know the difference between yams and sweet potatoes. The bad news is that it may still be hard to tell them apart, especially at places like farmers’ markets, which may not always label their produce. The good news is that as long as you’re buying a vegetable with dark purple or orange-hued skin and orange flesh, what you’ll get is probably good enough for most holiday recipes. Some say yams, some say sweet potato, but the belly is happy either way!