Hello all. As a career grocer I believe that the best way to contribute to this blog is to share some of my grocery knowledge and insight. I have been working in the natural food industry off and on for over a decade and continuously for the past six years. I have worked for big chains and small co-ops. Right now I am working for a certified organic grocery store chain (not target or walmart).
I was asked to explain the difference between a yam and a sweet potato. There is a great deal of confusion out there about the difference and it usually comes to a head around the holiday season (and by holiday season I mean Thanksgiving [the super bowl of food]). So what is the difference. Let me start out by saying that you probably have never actually eaten a yam. True yams are very hard to come by in this country. I have never actually seen one up close. Yams are an African root vegetable. They are big and bumpy. They look similar to a sweet potato, but they are not that closely related. They originated in Africa, but can be found in Asia, and Latin America as well. To prepare a yam you must first peel the tough outer skin, then pound it for a while, then boil the hell out of it. You can also fry them or pound them into a dough called fufu.
Now you may be saying to yourself "what the f is this guy talking about. I've had yams before. They sell them at my local market and they are delicious." Well, I agree that they are delicious, but I disagree that they are yams. What are commonly referred to as yams in this country are actually moist fleshed sweet potatoes. Etymologist are unsure when the mislabeling of sweet potatoes began. There are several theories. The most common is that they the name came over from Africa during the days of slavery. There are several Latin American cultures that call sweet potatoes by names similar to yam, so it is possible that the name came up from one of these nations. The names for both potatoes and sweet potatoes get very confusing in Central and South America. In any event, sweet potatoes are generally colloquially known as yams in the southern part of this country.
So basically, in a New Jersey grocery store, you will most likely find the drier sweet potatoes called sweet potatoes, while moist fleshed varieties are most likely referred to as "yams". That is not a hard and fast rule, but it has been my experience for the most part. The most popular varieties of "yams" are garnet, jewel, and hannah. Hannah have a lighter colored skin. Inside they have slightly yellow flesh. They are moderately sweet with a nutty flavor. Garnet yams have a darker exterior with an electric orange flesh. They are quite moist for a sweet potato and very sweet. Because of their moist flesh they are very versatile and can be prepared in many ways. Jewel yams fall somewhere between hannah and garnet. They have a yellow flesh with a nice nutty and sweet flavor.
I hope this clears up any confusion. Not a day goes by during the holiday season where a customer will ask me if we have sweet potatoes while standing directly in front of the yam display. I've gone through the spiel so many times. Sometimes customers just don't believe me or flat out tell me that I am wrong. I hope that you can help me spread the word about the difference between yams and sweet potatoes.
Sweet Potato (Garnet Yam):