{ subscribe_url:'//blogs.loc.gov/share/sites/library-of-congress-blogs/inside_adams.php' }

Candied yams or Candied Sweet Potatoes?

Sweet potato or yam? Our record isn't sure, but the flowering above resembles the flowering sweet potato

Sweet potato or yam?

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.

Thanksgiving Dinner, 1945. From the FSA/OWI Collection

Thanksgiving Dinner, 1942. From the FSA/OWI Collection

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.

5 Comments

  1. John
    November 17, 2009 at 12:10 pm

    As Popeye once noted, “I yam what I yam and that’s all I yam.” No sweet potato, he.

  2. Leslie
    November 21, 2009 at 8:57 pm

    It is interesting how custom sometimes dictates our definitions of what we believe something is. People believe that yams and sweet potatoes are the same. Why? Because we always called them yams! That’s why. Hmm.

    We have lost a curiosity we once had to go discover, as Jennifer did, the facts about a matter. We are content to go with the way it has always been. Or, we venture onto Wiki and find our answer there. But the practice of looking in a book, an encyclopedia or a reference guide on a particular subject that requires us to do anything other than double-click and scroll, seems ancient.

    Although Wiki breaks my heart a little, as those of us who love digging through text to find answers have found out that machines have turned our passion into an algorithm, it is still a better alternative than just believing things based on custom rather than fact.

    In the spirit of the upcoming holiday though, I think I will always believe that the pilgrams and indians sat down to a thanksgiving feast together in harmony to celebrate life together in the new world…even though my references (and Wiki) tell me otherwise.

  3. Jennifer Harbster
    November 23, 2009 at 1:46 pm

    Thank You Leslie. Your comment reminds me of the Auguste Comte that I have on my wall:
    “On ne connaît pas complètement une science tant qu’on n’en sait pas l’histoire.”
    “One does not know completely a science as long as one does not know its history.”

    Wishing everyone a happy and healthy Thanksgiving holiday!

  4. Marcus
    March 18, 2010 at 2:26 am

    Cool post you got here. It would be great to read more concerning this theme. Thank you for sharing this information.

  5. Nancy White
    November 24, 2016 at 2:30 pm

    Love these posts!

    Happy Thanksgiving!
    ❤️

Add a Comment

This blog is governed by the general rules of respectful civil discourse. You are fully responsible for everything that you post. The content of all comments is released into the public domain unless clearly stated otherwise. The Library of Congress does not control the content posted. Nevertheless, the Library of Congress may monitor any user-generated content as it chooses and reserves the right to remove content for any reason whatever, without consent. Gratuitous links to sites are viewed as spam and may result in removed comments. We further reserve the right, in our sole discretion, to remove a user's privilege to post content on the Library site. Read our Comment and Posting Policy.

Required fields are indicated with an * asterisk.