Did you know that most people consider sweet potatoes and yams to be the same vegetable? In fact, most grocery stores don’t even label them correctly. They simply call sweet potatoes “yams”.
They are actually two totally different vegetables.
Sweet Potatoes
Sweet potatoes are generally the only ones you will see in the grocery store. They are members of the morning glory family. They have smooth skin and are usually orange on the inside, though white, yellow, and even purple varieties are available. Sweet potato varieties are classified as either ‘firm’ or ‘soft’. When cooked, those in the ‘firm’ category remain firm, while ‘soft’ varieties become soft and moist.
Yams
The real yam is rarely sold in the United States. There are over 600 varieties of yams, and 95% of the yam production occurs in Africa. They are closely related to lilies and grasses, have rough, bark-like skin, and are starchier and not as sweet as a sweet potato. They can grow very large. Many different types of yams are cultivated and consumed mostly in Africa, Asia, and the Caribbean.
Here’s Why We Call Them “Yams”
Firm-fleshed sweet potatoes were first sold in the US. When soft sweet potatoes became commercially available, growers wanted to distinguish them from firm sweet potatoes. Africans in America noticed that the soft sweet potatoes resembled yams from their homeland and began calling them "yams". The name spread, and softer sweet potatoes gradually became known as yams.