What’s the Difference Between Yams and Sweet Potatoes?
Do you know the difference between a yam and a sweet potato? Most grocery stores offer two similar-looking tubers — some labeled as yams, and some as sweet potatoes. While much of the confusion stems from these names being used interchangeably in U.S. markets and in recipes, sweet potatoes and yams are actually two very different vegetables.
Would you be surprised if I told you that all those times you thought you were eating yams, you were likely eating a sweet potato, and that you probably haven’t ever actually had a true yam? And yet yam and sweet potato do mean different things in grocery stores. Here’s the scoop on yams vs sweet potatoes, with tips for getting the one you actually want at the grocery store.
Yams vs Sweet Potatoes: The Differences
Although the terms sweet potatoes and yams are often used interchangeably in the U.S., they are not the same thing. When it comes to yams vs sweet potatoes, the main differences are:
- Yams and sweet potatoes are completely different, botanically speaking. A yam comes from the Dioscoreaceae family, and sweet potatoes come from the Convolvulaceae family (aka the family of morning glories).
- True yams have rougher skin that’s typically brown, almost tree bark-like. Sweet potatoes have a thinner skin that’s reddish-brown, although it can vary.
- Yams have a starchier texture and sweet potatoes have a softer texture when cooked.
- In the U.S. you are most likely to find yams in international markets or specialty grocery stores. So, even if it’s marketed as a yam at an American grocery store, it’s usually a sweet potato.
What’s a Yam?
A yam is a tuberous root vegetable that is native to Africa and Asia, with the majority of the crop coming from Africa. They are related to lilies, and can be as small as a regular potato or jumbo in size (some grow five feet long!). Yams have a cylindrical shape with blackish or brown, bark-like skin and white, purple, or reddish flesh.
Compared to sweet potatoes, yams are starchier and drier. They’re carried in more grocery stores these days, but your best chance of finding them is to look in international and specialty markets.
What’s a Sweet Potato?
A sweet potato is a tuberous root vegetable that originated from Central and South America. There are many varieties of sweet potatoes, which come from the morning glory family. Skin color can be white, yellow, red, purple, or brown, while the flesh can be white, yellow, orange, or even orange-red. These vegetables have an elongated shape with tapered ends.
Among the numerous varieties of sweet potatoes grown in the U.S., there are two major types:
- Firm sweet potatoes, which have golden skin and paler flesh.
- Soft sweet potatoes, which have copper skin and orange flesh.
The two types of sweet potatoes cook differently. Firm sweet potatoes still remain firm and a little waxy after cooking, while the soft variety becomes creamy and fluffy (think: candied yams, which are in fact sweet potatoes).
Why Are Sweet Potatoes Called Yams?
So, if true yams from Africa aren’t very common in the United States, here’s the big question: What is the grocery store calling a yam? And is there any real difference between what a grocery store calls a yam and a sweet potato? Even though these “yams” aren’t true yams, there is a difference between the two, and you can actually shop smarter by knowing the difference in these labels.
Here’s an interesting little history lesson to explain why there’s so much confusion. As we mentioned above, there are two types of sweet potatoes: “firm” and “soft.” The firm variety was the first to be produced in the U.S., so when “soft” sweet potatoes began to be produced commercially, there was a need to differentiate it from its firm counterpart.
Since the “soft” sweet potatoes slightly resembled true yams, they picked up the name and became what you see labeled as “yams” in most U.S. grocery stores.
Common U.S. Grocery Store Labeling
- Yam — Soft sweet potato with a copper skin and deep orange flesh.
- Sweet potato — Firm sweet potato with golden skin and lighter flesh.
Ironically, when you want a classic baked sweet potato, with a crisp skin and fluffy orange flesh, or sweet potatoes for Thanksgiving sweet potato casserole, what you should buy will be probably labeled yam. Even though it’s not a yam. It’s a sweet potato. The soft kind. (You confused yet?)
But just to throw one more wrinkle into this, grocery stores often go rogue with labeling. We’ve bought “yams” (which are really sweet potatoes) that were indeed labeled as sweet potatoes.
The takeaway: Know what kind of sweet potato you want for your recipe (soft vs firm), and be alert to the yam/sweet potato labeling concept, but also use your eyes to look at the color of the skin and the flesh, if possible.