Sweet Potatoes Vs. Yams: What's The Difference?

If you're sitting down to Thanksgiving, are you eating candied sweet potatoes or candied yams with your turkey? The names yam and sweet potato have been used interchangeably for decades, but are they actually the same thing? 

Despite their name, sweet potatoes are not potatoes at all. In fact, while they are tubers, sweet potatoes are actually the root of a plant that's in the morning glory family (per Farmers Almanac.) According to Food Network, Christopher Columbus first brought these golden-colored roots back to Spain in 1493, and at the time, they were called "batatas" by the indigenous people who lived on the Great Antilles Islands. The Spanish then changed the name to "patatas." Later, the Spanish introduced the English to their discovery when they served a sweet potato pie to Henry VIII, after which the English called them "potatoes." 

What we know as sweet potatoes were simply called potatoes until 200 years later when Irish immigrants brought white potatoes to America. Once these became the default potato, the word "sweet" was added to the original batatas. So where do yams fit into all of this?

During the 1930s, some Louisiana farmers cultivated an orange variety of sweet potato, and to differentiate them from their golden cousins, the farmers began calling them "yams" (per Food Network). The word yam was already a southern slang word for sweet potato, which came from enslaved West African people who noted that American sweet potatoes reminded them a bit of an African vegetable called "nyami."

An African yam (or nyami) is very different from a sweet potato. It has a rougher brown husk, almost like a coconut, and can grow up to 45 feet long (via Food & Wine). The texture of a true yam is much more closely compared to yucca, and their flavor is much less sweet than a sweet potato. Food Network notes that African yams are often referred to as Nigerian yams, true yams, Ghana yams, puna yams, or white yams.

In America, sweet potatoes are still colloquially referred to both as sweet potatoes and yams, but some are looking to drop the word yam as slang. The African yam has cultural and spiritual significance to African people, notes Food & Wine, so using it as a nickname for a sweet potato isn't appropriate or accurate. Next time someone refers to a sweet potato as a yam, you can kindly set the record straight.