I don’t know about you, but when I go to purchase sweet potatoes or yams at the grocery store, more often than not I find myself standing there perplexed as to which is which. My initial thought, like many, is that a yam is determined by the dark colorful red interior flesh. Do you know the difference?
Actually sweet potatoes and yams are not even botanically related. One is a tuber, the other a root; they are grown in different countries, and they are not equivalent in nutrients. Here is a closer look.
Sweet Potatoes
Sweet potatoes are native to South America and now commonly
grown in the United States. Interestingly, they are not a potato at all, but instead are botanically related to the morning glory plant whereby the edible portion is the root. The skin is thin and smooth, and the vegetable is short, blocky and tapered at both ends. Sweet potatoes are available all year around, but peak harvest is in fall and winter when their flavors are the sweetest. There are many varieties of sweet potatoes. However, they ultimately fall into two categories: “soft” and “firm”.
The “firm” varieties were the first to be grown and introduced into the U.S. They often have a golden skin color with a creamy white flesh that tends to be a bit mealy and dry when cooked. In the mid-20th century, the “soft” varieties were introduced. These vegetables have skin colors ranging from white to yellow, red, purple, and brown, with a more pronounced interior flesh pigment of rich orange to red and even deep purple. When cooked, these vegetables are sweet and moist. In order to differentiate these two varieties, the decision was made to refer to the colorful “soft” varieties as “yams,” as African slaves were already referring to them as such due to the resemblance of the true yams grown in Africa. Today the USDA requires these so called “yams” to be additionally labeled as sweet potatoes.
Garnet, Jewel and Beauregard are common sweet potato varieties that have reddish brown skin and deep rich interior color that often masquerade as yams. These types are richer in beta carotene and antioxidants compared to the more pale versions.
Sweet potatoes are in abundance year around but are highly popular during the winter holidays. They can be easily cooked by placing them in a 400-degree oven for about an hour, or by wrapping a paper towel around them and microwaving until soft to the touch. Due to their higher moisture content, the hissing sound of the steam escaping and the oozing of the liquid during the final stages of cooking is another determination of doneness. Hence, take caution when handling these fresh cooked vegetables, as they can cause burns.
Yams
Yams are native to West Africa and Asia and are closely related to lilies and grasses. The word “yam” is an African expression meaning “To eat.” The edible portion of the plant is the tuber and has been known to grow up to seven feet long. The outer skin is black with a bark-like appearance, and interior flesh ranges from white to purple and red colors. When cooked they have a starchy, crumbly and drier texture as compared to sweet potatoes. Yams have a long storage life, providing nourishment during the long winter months when food might be scarce. Yams are often prepared by peeling/boiling/mashing- drying or grinding into a powder and used in porridge. Since nearly 95 percent of true yams are imported from the Caribbean, they are more difficult to find in the U.S. unless shopping at international markets.
Whether purchasing sweet potatoes or yams, select vegetables that are heavy for theirsize and free of soft spots and sprouts. Store them loosely in a dry cool and dark area with adequate ventilation. Remember, color means nutrition! To help you get the best bang for your buck, choose foods rich in color, since in most, the brighter the color, the more health benefits are offered. So the next time you are standing in the produce isle pondering which variety to buy….reach for the rainbow!
For more information check out this video and here for nutritional comparison.
