Yesterday my father-in-law and I had a bit of a debate about the difference between sweet potatoes and yams, so I thought I’d do a little research. I always thought that sweet potatoes were white-fleshed things that looked pretty much like normal potatoes, while yams were the orangey things in the supermarket that I actually use when I tell people I’ve made “mashed sweet potatoes”…but it turns out that I’m wrong.

Sweet potatoes are the lovely creatures pictured above on the left. Originating in South America, they come in dozens of varieties, but it’s only us North Americans who consume the orange ones. These are usually labeled “yams” in supermarkets, but apparently supermarkets can be wrong. There’s also a paler-skinned, more crumbly variety, which is what supermarkets commonly call “sweet potatoes.”

True yams have white flesh, are relatively flavorless, and are not even distantly related to sweet potatoes. They’re pretty hard to find in the U.S., and where they are popular (Central and South America, the West Indies, and parts of Asia and Africa) they’re generally used as a blandish backdrop for more flavorful ingredients. Yams can grow up to seven feet in length, and have brown or black, tree-bark-like skin.

Sources: Homecooking.about.com; Bonappetit.com