Do you find yourself using the terms sweet potato and yam interchangeably? Join the club…
What you need to know:
We’ll start with the bottom line. If you live in the US and buy your groceries in a supermarket, you are most likely buying sweet potatoes.
Yams and sweet potatoes are actually 2 different species of the angiosperm (flowering plant) family. According to the records of the Library of Congress:
Yams are a monocot (a plant having one embryonic seed leaf) and from the Dioscoreaceae or Yam family. Sweet Potatoes, often called ‘yams’, are a dicot (a plant having two embryonic seed leaves) and are from the Convolvulacea or morning glory family
Yams have their roots (pun intended) in Africa and Asia, where hundreds of varieties are cultivated and eaten as a staple. “Yam” means “to eat” in various African languages / dialects.
So how did sweet potatoes come to be called yams?
There are 2 major types of sweet potatoes in the US, the lighter colored more round variety, and the orange elongated variety. In colonial times, African slaves brought to the Americas mistakenly identified the latter as the “yam” from back home. Fast forward a few hundred years, the USDA decided to formally differentiate the 2 varieties of sweet potato by calling the darker orange ones yams, thus perpetuating the tradition from the late 17th century.
And what do real yams look like? Here’s an example: