Given how plentiful they are in autumn, it’s no wonder you’ll see mounds of sweet potatoes and yams for sale at supermarkets around Thanksgiving.
But did you know that one of them has been posing as another type of vegetable for generations?
When buying them you’ll notice they have a similar shape and size and there’s a good reason: they’re both varieties of sweet potato.
The story goes that, decades ago, an American seller decided to call the copper-skinned, orange-fleshed variety of sweet potato a yam. He did that to help distinguish it from the tan-skinned, pale-yellow-fleshed type, which is still called a sweet potato.
Calling it a yam was an odd decision, given that a sweet potato is not a yam. According to The New Food Lover’s Companion, a “true” yam is from a different plant species and is a staple ingredient in places such as South America and Central America, as well as some Asian and African countries. It can be much larger than a sweet potato and has a light flesh and rough skin that’s peeled before cooking.
While real yams have never been widely available here, orange-fleshed sweet potatoes have, and we obviously bought into the idea of calling them yams. The upside is that it did help distinguish it from the pale-yellow-fleshed type.
Orange-fleshed sweet potatoes, a.k.a. yams, are denser, moister and sweeter than the pale-yellow-fleshed variety. The latter variety is also starchier and nuttier in flavour. Because of those differences, they are suited to different styles of preparation.
For example, if you need a sweet potato to hold its shape when cooked for use in a salad, while also adding a vibrant colour, the orange-fleshed variety is best. The yellow-fleshed variety, because it’s starchy like a baking potato, is great for roasting, frying or boiling and mashing.
Both types can be combined in a dish, as I did in my coconut-milk-based, Thai-style curry recipe. The paste flavouring the curry is…