When I was first introduced to whole foods, plant-based (WFPB) eating, I followed recipes by Deliciously Ella who is based in England. Sweet potatoes were often used, however, from a North American perspective, the sweet potato looked suspiciously like a yam! Then, during my last trip to England, I noticed that the supermarkets were full of what I understood to be “yams” but were abelled as “sweet potatoes.”
As a result of this experience, I had wondered whether this was a British misunderstanding! However, it turns out this is not the case and the British are correctly naming their tubers. However, it seems it is a different story in North America! As I explored this mystery, I discovered I was not alone and, apparently, sweet potatoes and yams are two of the most confused root vegetables.
Are sweet potatoes and yams the same thing?
The short answer is no. Although these two vegetables are often used interchangeably, they appear not to be even related. Sweet potatoes are from the Convolvulaceae (morning glory) family and are native to tropical parts of the American continents. Apparently there are over 400 different sweet potato varieties around the world and the skin and flesh color can be white, yellow, red, purple or brown.
A Rainbow of sweet potatoes:
As outlined in Alyse Whitney’s article, what’s the difference between a sweet potato and a yam, some varieties of sweet potato are:
Orange Sweet potatoes
The orange sweet potato is often referred to as a yam in North America. With orange skin and varying shades of orange flesh, this potato has become a popular meat replacement in plant-based cooking because of its ability to “carry spices”. Within this group, there are a number of different types (Beauregard, Garnet, and Jewel). They are interchangeable with subtle differences in flavor, sweetness, and moisture levels.
White sweet potatoes
This sweet potato is a great middle ground between the orange sweet potato and a russet potato. With smooth cream-coloured skin and a cream/whitish colored flesh that becomes yellow when baked, this variety has a slightly more crumbly and dry texture and is slightly less sweet.
Purple sweet potato
These are a deep purple both on the outside and can be purple or white on the inside. They are fairly dry on the inside and not very sweet. The colour tends to bleed out when boiling so it may be preferable to either roast, sautée, or fry.
Photos Top: orange sweet potato; Bottom Left to Right: white sweet potato, purple sweet potato with white flesh, and yam.
If not a sweet potato, what is a yam?
True yams are members of the Dioscoreaceae family. They are native to Asia and Africa and can reach weights of up to 150 lbs. The yam is harder than a sweet potato and takes a long time to cook to softness. The bark-like skin is tough with a dry, starchy non-sweet flesh more like yucca in texture and flavor.
As with sweet potatoes, yams can be boiled, roasted, baked or fried but because yams are quite dry and starchy, they tend to work best with a moist sauce on the side or cooked in a stew or a soup.
What is the nutritional value of a sweet potato and yam?
According to Healthline, although the sweet potato and yam are both healthy foods, the sweet potato contains a bit more vitamin C than yams and more than triple the amount of beta-carotene, which converts to vitamin A in the body..
Alternatively, raw yams are slightly richer in potassium and manganese which are important for good bone health and proper functioning of the heart, growth and metabolism.
Both sweet potatoes and yams are good sources of other micronutrients, such as B vitamins, which are vital for many bodily functions, including producing energy and creating DNA.
Why the confusion between sweet potatoes and yams?
Everyday Mysteries explains that sweet potatoes fall into two categories known as firm or soft. After cooking, the former remains hard and the latter becomes soft and moist. In the United States, firm varieties of sweet potatoes were produced before soft varieties and when the latter were first grown commercially, there was a need to differentiate. Because the soft sweet potatoes resembled the yams in Africa, they began to be refereed to as yams.
Recipe for sweet potatoes
Regardless of colour, a quick and easy way to enjoy these potatoes is to cut them into bite-sized chunks and rub them with about a tsp of paprika and a tsp of cinnamon with some olive oil.
Spread the chunks evenly on a baking sheet and cook at 350-375°F (175-190°C) for about 50 – 60 minutes until the outside is crispy and inside is soft.
The sweet potato mystery is now clearer to me! The orange-fleshed vegetable labelled as a sweet potato in the UK, contrary to what I originally thought, is not a yam. I have never tried to find a true yam but it seems that they are more likely to be found at an international market rather that the local supermarket.
This certainly helps when following recipes from England as I now know what to use. Regardless of their name, it does not change the fact that they are a versatile, delicious and nutritious vegetable which can be used in so many tasty ways.