All About Sweet Potatoes

Pun aside, it really is amazing what you discover when you examine the lowly sweet potato.  I was raised on "white" potatoes myself, and except for Thanksgiving, Christmas and Easter, I don't recall eating sweet potatoes that often.  They were considered more of a holiday specialty casserole dish to be made or topped with things like little red cinnamon candies called Red Hots®, pecans, maple syrup, marshmallows, brown sugar, orange juice, and spices such as nutmeg.  In fact, it was a very long time before I knew how the plain, unadorned meat of a sweet potato actually tasted.  It didn't take long to become a real fan.  Since I often like to know exactly what I'm putting into my mouth, I wanted to learn more about them.

First, let me define a sweet potato as it is known in the world of Botany.  It's classified as Ipomoea batatas, an herbaceous perennial vine and dicotyledonous plant belonging to the family Convolvulaceae.  Those of you who love to grow morning glories will recognize that they belong to the same family.  Indeed, the bloom of the sweet potato very much resembles that of a morning glory.  I. batatas is a large, starchy, sweet-tasting tuberous root that is an important root crop around the world.  While not the sole plant crop in its genus, it is the only one of major importance.  The sweet potato is only very distantly related to the common potato (Solanum tuberosum).

The softer and frequently larger variety of tuber that is known in parts of the country as a yam is not a sweet potato.  They are botanically distinct plants with the various types of true yams all belonging to the monocot family Diascoreaceae.  To further confuse the issue, many grocery stores continue to label sweet potatoes as "yams", especially around the holidays.  To prevent confusion, the USDA now requires sweet potatoes labeled as "yams" to additionally be labeled as "sweet potatoes".  So when is a yam not a yam?  When it is a sweet potato.

I hope to clarify the potato ID issue a bit further here by adding a few historical details.  The word potato originally referred to a type of sweet potato rather than the other way around.  The English confused the two plants one for another, and in many of their writings detailing agriculture and plants, no distinction is made between the two at all.  The 16th-century English herbalist, John Gerard, referred to common white potatoes as "bastard potatoes" or "Virginia potatoes" while referring to sweet potatoes as the "common potatoes".  Since so much of our historical record came over with the Puritans and Pilgrims, it stands to reason that the confusion surrounding all these various tubers continued.  This I do know: when is a potato not a potato?  When it is a sweet potato.

Now that I've hopefully cleared up a bit of the confusion, I trust you know which potato is which, at least generally-speaking.  From here forward, I'm referring only to the wonderful sweet potato.

China produces the most sweet potatoes worldwide, providing about 80% of the world's supply.  I guess you could say that by comparison, US production would be considered small potatoes (groan).  In 2004, the Chinese produced approximately 80.5 million metric tons, with about 60% of that going to feed pigs and other livestock.  In comparison, the US produces less than a million metric tons annually.  My figures may not be exactly accurate, so please don't write me about that.  Right about this point I got weary of calculating pounds, tonnes, short tons and metric tons as well as trying to determine which statistics and sources appeared the most credible.  I have now declared such figures, charts and so forth to be beyond the scope of this discussion.  I believe that's what writers often do when they don't want to fool with something.  Seriously, if you are a person who loves statistics, there are plenty of them out there regarding sweet potatoes and who grows how much of which kinds, who does what with how much of each kind they grow, and exactly how they are likely to do it.  While interesting, it really is not within the intended scope of this article.

However, one of the main emphases of this article is the nutritional benefits derived from eating sweet potatoes.  And there are many.  Here's a brief description of what lies beneath their skin.   Along with simple starches, sweet potatoes are rich in complex carbohydrates (good carbs), dietary fiber, beta carotene (a Vitamin A equivalent nutrient), Vitamin C, and Vitamin B-6.  A reputable study ranked sweet potatoes highest in nutritional value of any vegetable.  According to the study criteria, sweet potatoes earned a score of 184 points which was 100 points higher than the next veggie down the list, the common potato.  While ranking high on most nutritional indices, they rank low on the Glycemic Index.  This means they don't tend to cause your blood sugar to spike after you eat them, and that makes them a good choice for diabetics.  Sweet potatoes are also a boon to dieters because they tend to produce a feeling of satiety.  In other words, they are just plain good for just about everybody.  I once read that a person could actually live on sweet potatoes.  In fact, that was the assertion that piqued my curiosity enough to learn more about them.  While they are definitely nutritional powerhouses and a person could most likely subsist on them for awhile, I haven't come across any facts to indicate that is true for the long haul.  They are not a complete food.  Sweet potatoes lack enough protein and enough of the necessary total amounts and diversity of vitamins and minerals needed to support overall good health indefinitely.  They are, however, one of the most nutritious foods you can eat.   A large baked or steamed sweet potato has approximately 165 calories.  So go ahead and splurge on the butter.

Should you now decide you want to grow your own sweet potatoes, that's great!  They require a long, warm and totally frost-free growing season of 100-140 days.  That makes them easier to grow in some parts of the country than in others.  One method that just about anyone can use to grow sweet potatoes is in bags.  Yes, I said bags.  Obtain as large a grow-bag (either commercial or homemade) as you can comfortably handle and make sure it has excellent drainage.  Fill the bag with potting soil (not soil from out of the ground or garden) and plant with your own homegrown organic sweet potato slips (see photo to right).  Keep the soil moist but not soggy, and keep the bag out of the hottest sunlight until the plants are established.  Before the first frost, simply dump the contents of the bag out onto a tarp and harvest your sweet potatoes, all without any digging.

While sweet potatoes enjoy a long history of use and value in many cultures around the world, that's not so much the case in this country.  However, they do have their fans and their numbers are steadiy growing.  If you're ever in Benton, KY, on the first Monday of April, you might want to attend the Tater Day Festival.  Gleason, TN, celebrates its love of sweet potatoes on Labor Day weekend with the Tater Town Special.  The National Sweet Potato Festival and Yambilee is held annually during the entire first week of November in Vardaman, MS (pop. 1278 give or take a few), which has also declared itself "The Sweet Potato Capital".  I don't know how the food at these events compares with the food at other festivals, but I'd be willing to bet it just might be a whole lot more nutritious.

  Grandma's Red Hot Southern Sweet Potatoes
3 & ¼ lbs. of sweet potatoes, peeled and cubed
¼ cup butter or margarine, melted
½ cup packed brown sugar
1 & ½ cups cinnamon red hot candies
¾ cup water
1 (10 oz) package of miniature marshmallows

1. Place the sweet potatoes in a large saucepan with enough water to cover. 
Bring to a boil and cook over medium heat until tender, about 25 minutes. 
Drain water and place potatoes in a large casserole dish.
2. Preheat oven to 350º.
3. In a medium bowl, stir together butter, brown sugar, red hot candies and water. 
Pour over potatoes in the casserole dish.
4. Bake for one hour or until sweet potatoes are soft and candies are melted. 
Top with marshmallows, if desired, and return casserole dish to the oven
for 10 minutes to melt and brown.

Photo credits:
Thumbnail and all photos with exception of top photo and photo of sprouting sweet potato, courtesy of Wikimedia Commons, some rights reserved