Yams and Sweet Potatoes are the Same Thing, Right?


The simple answer would be no.

Today in the United States the USDA requires the name yam to be joined with the word sweet potato. But, true yams are a form of an edible tuber and a monocot (having one embryonic seed leaf) from the Dioscoreaceae family. Sweet potatoes, on the other hand, are a dicot (having two embryonic seed leaves) and are from the Convolvulacea family, or morning glory family. So then, where did the origins of the name yam come from? By the 1580’s the word igname, from the Portuguese word inhame, or Spanish igname, originated from a West African language. It was a mispronunciation of the term “to eat” and is probably the source of the American word “yam”.

This variety of yam has a tree bark exterior and a slightly slimy white interior. When cooked it tastes like a lightly sweet white potato.

There are hundreds of varieties of yams, with most of them grown in Africa, though they can be found in different varieties all over the world. Colors can be white, yellow or even purple.  After cultivation yams can have as long as a six month shelf life and can be eaten the same way we do a modern white or sweet potato: boiled, fried, frittered, and mashed.  In parts of Africa the yams can be milled and turned into a powder, which when mixed with water, turns into a thick starchy paste used in puddings, stews and soups.

When looking at a yam and a sweet potato side by side it is easy to see the difference. The yam is a big, round or oblong tuber, which can grow as long as one’s arm.  The skin looks remarkably like the bark of a tree.  The inside can be slightly slimy. The yams we procure end up tasting like a lightly sweet white potato. The sweet potatoes, which are grown in both the Palace and Wythe gardens, can be long and skinny, or rounded, but rarely reach the size and shape of the yam.  Their orange flesh is not slimy, and when cooked it smooth and sweet.

Locally sourced yams (white half moons) and sweet potatoes grown in the Palace gardens showcase the best of Virginia’s bounty.

When we can find yams they are used exclusively at the Wythe kitchen. Though Mr. and Mrs. Wythe are wealthy people, they are also Virginians, and as Virginias would be familiar with foods on their table that an English aristocratic family would possibly shun: yams, okra, tomatoes, corn and certain squashes. These flavor profiles would eventual develop into what is now identified as Southern Foodways. If you look through 18th century cookery books potato recipes are often lacking. In English cookery books or treatises, they are referred to as food for the working classes. They simply were not the staple that they are in today’s American diet.

Though not common in your big box grocery stores yams can be occasionally found for sale. If not, try an International or Asian market, or if you’re lucky enough to be close to an African market you’ll be sure to find them. If you do find a yam in your local market don’t be afraid to try them. Anything you can do with a white or sweet potato you can do with a yam. Enjoy!

From: Letters, by the Earl of Dundonald, on making bread from potatoes, to the inhabitants of Great Britain; And particularly to the inhabitants of Great Brittan, written in 1791, by Archibald Cochrane, Earl of Dundonald

From Cookery, and pastry. As taught and practised by Mrs Maciver, teacher of those arts in Edinburgh, by MacIver, Susanna, 1784.


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