Okay, let’s straighten this out once and for all. Those big orange roots you find in the grocery store are not yams. Got that? As a matter of fact, it’s a good bet that most of the people who just read that have never even seen a yam.
Sweet potatoes came to be called yams because they’re kind of/sort of similar, both starchy/sweet root vegetables, but they’re quite distinct; a sweet potato is far sweeter and much smoother than a yam. The most important distinction is that yams don’t grow in the South, but sweet potatoes do, in glorious profusion. Sweet potatoes have always been a staple of Southern tables as well as a reliable source of income. The sweet potato is the state vegetable of North Carolina, and the Sweet Potato Capitol of the World is Vardaman, Mississippi. (If tells you any different, they’re a double-dog liar who needs a thorough ass-kicking.
Still and all, you’re bound to find cans of yams in many local grocers, but due to USDA requirements, most inevitably you’ll find “sweet potatoes” somewhere on the label.