Published on 12/17/99

Sweetpotatoes or Yams? Both are Yummy

As the holidays draw near, we begin planning what to serve at family dinners. One question comes up every year: What is the difference between a sweetpotato and a yam?

For those of us middle-aged folks raised in the South, some of our most precious holiday memories center on food and good smells from the kitchen. As children, we had just come out of the Depression and World War II. Money was short and food had been rationed, but we still had the Victory Garden and every one shared with those less fortunate.

Sweetpotatoes were dependable crops that could be stored and used throughout the winter.

I remember the smell of baked sweetpotatoes, luscious pies -- baked and fried -- and candied sweetpotatoes with marshmallows on top. My favorite was sweetpotato "surprises." Mother would mash the left-over baked sweetpotatoes, form them into golf-ball sized mounds, punch a hole into the center and fill it with one or two small marshmallows. Then she'd reform the ball, roll it in coconut and chopped pecans, and bake it just long enough to melt the center.

Sweetpotatoes (Ipomoea batatas), a New World crop from tropical America, were around in prehistoric times. Yams (Dioscorea alata L.) are from West Africa and have been cultivated for about 50,000 years.

The African word nyami, referring to the starchy, edible root of the Dioscorea plants, was adopted in its English form, yam. What many in the U.S. call yams are actually sweetpotatoes. Although the terms are generally used interchangeably, the U.S. Department of Agriculture requires that the label "yam" always be accompanied by "sweetpotato."

There is a difference between the two. Yams are rough, scaly tubers with white-flesh that is dry and tastes very starchy. They must be boiled first to remove alkaloids before you cook them.

Sweetpotatoes are smooth-skinned, moist and sweeter tasting. They have one of the highest Vitamin A contents of any food and can be prepared a variety of ways.

Not all sweetpotatoes are the same. There are several types of sweetpotatoes. One type is white-fleshed, somewhat drier tasting, and preferred by some over the moist, yellow-fleshed ones.

The Jersey type is also yellow-fleshed, but is drier tasting than the normal moist yellow-fleshed sweetpotato. The Southern type is moist-fleshed, syrupy and sugary.

The amount of sugar in sweetpotatoes varies with cultivars. However, most of the current varieties are quite sweet and are an excellent, concentrated source of vitamins and minerals.

Sweetpotatoes can be boiled, fried as french fries, made into chips or candied, but to most of us sweetpotato fans baked is still best. So, put sweetpotatoes in a cold oven, turn it to 425 degrees for an hour or so depending on the size of the roots and enjoy.

Wayne McLaurin is a professor emeritus of horticulture with the University of Georgia College of Agricultural and Environmental Sciences.