What's the Difference Between Yams and Sweet Potatoes?
I was born in Vardaman, Mississippi, the self proclaimed "Sweet Potato Capital of the World." Since my current home state of North Carolina produces far more sweet potatoes—about as much as Mississippi and the other top-producing states of California and Louisiana combined—it seems that Vardaman should consider relinquishing this title. They maintain, however, that what they lack in quantity, they make up for in quality. In fact, one Vardaman farmer recently reported that visiting farmers from North Carolina took Mason jars of his soil back to North Carolina State University in an attempt to decipher the secret to the silky sweet taste and the smoother, tighter skin of Vardaman-grown sweet potatoes.
If there is one question that everyone I meet seems to have, it is the difference between yams and sweet potatoes. That confusion is two-fold and centuries old, beginning with the slave trade. Ships transporting enslaved Africans to America were provisioned with true yams (Dioscorea), a large hairy root of tropical origins. In America, where there were no yams, they were replaced with the New World sweet potatoes (Ipomea batatas), which were paler in color and drier in texture than today's popular varieties. Slaves took to calling them by the West African word "nyami," which was Anglicized to "yam."
That confusion was further compounded in the 1930s when the USDA allowed Louisiana to brand the moist, bright orange Puerto Rican variety of sweet potato as a yam, however incorrect that designation may be. By capitalizing on its colloquial name, Louisiana hoped to distinguish its sweet potato from the inferior varieties grown at the time in Virginia, Maryland, and New Jersey. Call them what you wish, just know that in the United States yams are actually a variety of sweet potato.
April McGreger is the owner of Farmer's Daughter, a North Carolina-based artisan food company.