How Are Yams and Sweet Potatoes Different?

What's the Difference Between Yams and Sweet Potatoes?

November 16, 2020
Yam Vs Sweet Potato

Are sweet potatoes the same as yams? No… and yes. When orange sweet potatoes were first introduced, grocery stores called them “yams.” Why the confusion? Let’s get to the root of this matter—and give you the scoop on the difference between yams and sweet potatoes! 

How Are Yams and Sweet Potatoes Different?

Yams and sweet potatoes are confused. Literally and botanically speaking, the two are not related. 

Both the yam and the sweet potato DO grow underground and have yellowish-orange flesh, but there the similarity ends; they are not the same plant species.

Yams vs. Sweet Potatoes

What are yams

  • Yams are big edible “tubers” that are categorized as monocots (plants having one embryonic seed leaf) and belong to the genus Dioscorea.
  • Yams grow in tropical and subtropical climates, primarily in South America, Africa and the Caribbean. According to horticulturist U. P. Hedrick, the word yam means “to eat” in the dialect of Guinea.
  • They grow two to three feet long and some can weigh as much as 80 pounds! Imagine bringing home a yam that big from the market!
  • Real yams have rough, brown, scaly skin and white flesh that is dry and starchy; however, when cooked properly, yams have a mild, earthy flavor with a subtle sweetness. (Note: Most yams are mildly toxic when raw and must be cooked prior to consumption.)
  • Yams are very nutritious, offering carbs, fiber, potassium, vitamin C, vitamin B6, and vitamin E. In addition, tubers keep 4 to 6 months when stored properly.

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Image: Yams versus sweet potatoes. Credit: https://ncsweetpotatoes.com/

What are sweet potatoes?

  • Sweet potatoes are edible “roots” that are categorized as dicots (plants having two embryonic seed leaves) and are from the Convolvulacea or morning glory family.
  • They are native to the Americas, growing best in both tropical and warm temperate regions. The sweet potato has long been a favorite crop in the United States, especially in the Southeast. Over 50% of the country’s sweet potatoes are grown in North Carolina.
  • In terms of size, sweet potatoes are generally about 5 inches long and weighing 4.5 ounces; they always taper at the end and have thin skin. Sweet potatoes store in the pantry for about 2 to 3 weeks; never put them in the refrigerator, as they’ll get hard and develop an unpleasant taste.
  • Sweet potato varieties come in different colors (orange, white, yellow, or purple) and have a naturally sweet, creamy, moist texture. Often, it’s served as a colorful side dish, especially around Thanksgiving.
  • Sweet potates are very nutritous, containing protein, calcium, iron, sodium, vitamin A, and beta-carotene.

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Image: Four different kinds of sweet potatoes: Jewell, Jersey, Oriental, Garnet

So, Why Do People Call Sweet Potatoes “Yams”

Why is the orange-fleshed sweet potato variety that we commonly eat today called a “yam” when it’s not the same plant species? How did this start?

The two became entwined in this country by household vernacular, in part, through the work of a publicity campaign. Earlier this century, sweet potatoes were only white or yellow. The orange sweet potato was cultivated in the 1930s and it was larger, sweeter, more moist, and fleshier compared to the smaller, yellowish, and drier-fleshed varieties. A superior sweet potato!

To differentiate the orange sweet potato from the white and yellow ones, it was called a “yam” because it looked similar to the African vegetable. 

Today, the name “yam” has stuck as an interchangeable term for orange sweet potatoes in America. Whether you do find white, orange, yellow, or even purple sweet potates, they are all interchangeable in cooking, but bring different tastes, textures, and colors to your plate.

The Verdict?

Whatever you call it, you are mostly likely buying a sweet potato in your grocery store, unless you shopping in an urban Hispanic market or international market.

Interestingly, the U.S. Department of Agriculture requires labels with the term “yam” to be accompanied by the term “sweet potato.” Also, the preferred wording from the state sweet potato commissions seems to be “sweetpotato” (one word). Apparently, the reasoning is that it’s a unique crop, not a potato that happens to be sweet (sweet potatoes aren’t related to potatoes, either—but that’s another story). 

However, if you want to call this vegetable a “sweet potato” or a “sweetpotato” or a “yam” out of long tradition, be our guest! Our Southern readers love their candied yams!

We hope that you enjoyed learning the “root” history of this orange, nutritious, delicious vegetable.

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Sweet potatoes are often cooked as side dishes; for example, see our popular Pecan-Crusted Sweet Potato Casserole.

See our favorite sweet potato recipes including sweet potato souffles, sweet potato pie, sweet potato fries, and more! 

Trying to grow sweet potatoes? Check out our Sweet Potato Growing Guide for tips!

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Reader Comments

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Yam!

Like a famous sailor used to say! " I yam what I yam and that's all that I yam. I'm Popeye the sailor man!! "

Sweet potatoes

In the 1970s and 80s I showed my city kids how to grow sweet potato vines indoors in water. They we're amazed how the vines trailed. Growing sweet potatoes is a rewarding, educational, and beautiful lessons for children to experience.

Yams vs. Sweet Potatoes

First, neither one is a "potato"....sweet potatoes are from the Morning Glory family while yams are from the grasses and palms family (hence the rough, dark, bark-like skin). A yam has a darker skin that is rough and almost hairy and is almost cylindrical in shape. A sweet potato has tapered ends with a lighter more delicate skin and either one can have different colored flesh.
Taste:
Yams are starchy, dry, take longer to cook and need more butter (milk, cream, etc.) to make them more palatable.
Sweet potatoes on the other hand are, well....just sweeter, naturally softer, much moister and easier to prepare.
In the end, yams and sweet potato are interchangeable labels thanks to a marketing campaign in the 1930's. It also doesn't help that the FDA has no standard of identity for either one and in supermarkets you will see yam and sweet potato labels interchanged.
Hope this helps.

sweet potato vs. Yam

informative read but disappointing cause.....I STILL can't tell the diff. when I go to the store. I suspect they use the two words interchangably

comment

i like sweet potato good for heath and to eat

SweetPotato vs. yam.

Greetings and thank you for your “Sweetpotato” information. I spent 20 years trying to explain and prove to our Office Staff we were not eating Yams. I never really succeeded. That was in the 70s & 80s. I will try finding a few Friends ,to supply them with a copy of your blog. It may help, though being an implanted Yankee , they will not be sure we are correct.
I love The Old Farmers Almanac. Remembering reading it as a child. Gail

I have read a couple of the

I have read a couple of the blog posts on your wietbse since yesterday, and I truly like your way of blogging. I bookmarked it to my bookmark web site list and will be checking back soon. Please visit my site also and let me know your opinion. -3Was this answer helpful?

when is time to dig sweet

when is time to dig sweet potatoes that was planted this pass april 13th.the kind was beaurgard

Hi Colon, the variety you

The Editors's picture

Hi Colon, the variety you planted is 100 days to harvest, so you should be able to count from when you planted to get an accurate harvest date. Otherwise, you can dig up some of the young potatoes now if you wish, but wait to harvest the full crop until just before the first fall frost in your area. Enjoy!

I planted sweetpotato vines

I planted sweetpotato vines this past summer and was surprized to fine HUGE potatoes at the end of the vines upon our first frost here in Asheville, NC. I tried one out in the oven and it was to funky to eat. I did not fertilize the vine at all and the soil is semi-soft. Are these edible? If so, what type of fertilizer is best other than compost? I did some composing from time to time in the area.