Have you ever wondered what the difference is between a sweet potato and yam? I have. I found myself in a market looking for fresh sweet potatoes for a sweet potato salad recipe. I searched the produce aisle, without success. So I asked the produce manager for help. He told me to use the garnet or jewel yams. “But my recipe calls for sweet potatoes,” I cried. He replied, “The yams are just like sweet potatoes.”
I took his advice, but when I got to the Library the next morning I thought this would make a perfect Everyday Mystery— What is the difference between sweet potatoes and yams?
I hurried down to the reading room and grabbed The Oxford Companion to Food and the Cambridge World History of Food to find my answer. What we call a yam in the United States (e.g., garnet yam or jewel yam) is in fact a softer variety of sweet potatoes. True yams, native to African and Asia, are drier and starchier than sweet potatoes.
To supplement this culinary history, I needed to understand the botanical relationships between the two. Botanically, a sweet potato and a yam are both flowering plants, but that is where the similarity ends. Yams are closely related to lilies and grasses, while sweet potatoes are part of the morning glory family. I learned that the sweet potato isn’t even a real potato!!
I felt misled. For so many years, I have claimed the yam as one of my favorite vegetables. In fact, as a youngster, I used to sing songs about them. The “I love yams song” was a favorite. After all these years, I have now recognized that it is the sweet potato I love.
So as you sit down to a Thanksgiving dinner of candied yams, you can share this tidbit with your friends and family – that you are not eating yams, you are eating sweet potatoes.
You can read more about the difference between a yam and a sweet potato from our Everyday Mystery Web site.