Since it’s approaching Thanksgiving, I was reminded of a conversation we had, I think, a couple of years ago. Claire was discussing what to have for Thanksgiving dinner and I mentioned liking sweet potatoes like her sister, Terry, made. She thought that was a good idea and she said she thought we should have mashed potatoes and yams.
I remembered that my grandparents always referred to sweet potatoes as “yams,” and I wondered why. I know that in the South, a popular dish is candied yams — I never heard it called candied sweet potatoes.
Well, naturally, this issue called for some of my extensive research. Turns out that this time my extensive research got a lot more involved that I had originally intended. But it was new information to me — here’s what I found:
Sweet potato varieties come in different colors — orange, white, yellow or (sometimes) purple. I alway thought sweet potatoes were orange. It turns our that the orange sweet potato is a recent thing. Until the 1930s sweet potatoes were only white or yellow. Then in the 30s, the orange sweet potato was cultivated and it was larger, sweeter, more moist, and fleshier compared to the smaller, yellowish, and drier-fleshed varieties… someone had come up with 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 an African vegetable with that name. Today, the name yam has stuck as an interchangeable term for orange sweet potatoes in the US.
Here’s some extensive research information I don’t really understand, but it seems important (and interesting) so I’ll pass it along.
Yams are big edible “tubers” that are categorized as monocots (plants having one embryonic seed leaf) and belong to the genus Dioscorea.
Sweet potatoes are edible “roots” that are categorized as dicots (plants having two embryonic seed leaves) and are from the Convolvulaceae or morning glory family.
Yams grow in tropical and subtropical climates, primarily in South America, Africa and the Caribbean.
Sweet potatoes are native to the Americas, growing best in both tropical and warm temperate regions.
Yams can reach two to three feet long and some can weigh as much as 80 pounds.
Sweet potatoes are generally about 5 inches long and weigh about 4.5 ounces. They always taper at the end and have thin skin.
So back to the question, why do people call sweet potatoes yams? Basically to differentiate the orange sweet potato from the white and yellow ones. Today, the name “yam” has stuck as an interchangeable term for orange sweet potatoes. Whatever you call it, the odds are very high that you are buying a sweet potato in your grocery store.
My extensive research also discovered that the U.S. Department of Agriculture requires labels with the term “yam” to be accompanied by the term “sweet potato.” And — the preferred wording from the sweet potato commission(s) is “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.
So there you have it — seems like this time my extensive research got to the “root” of all the confusion.
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