A: Yams and Sweet Potatoes
I have an old recipe for a Yam pie. In the grocery store, I found orange potatoes labeled sweet potatoes and orange potatoes labeled yams. They all look the same to me. What to do? I consulted the ultimate authority, The Library of Congress, to discover that yams and sweet potatoes have nothing to do with each other, and you essentially won’t find anything that resembles an official yam on your grocer’s shelf.
Yams are closely related to lilies and grasses. Native to Africa and Asia, yams vary in size from that of a small potato to a record 130 pounds (as of 1999). There are over 600 varieties of yams and 95% of these crops are grown in Africa. Compared to sweet potatoes, yams are starchier and drier.
The many varieties of sweet potatoes (Ipomoea batatas) are members of the morning glory family, Convolvulacea. The skin color can range from white to yellow, red, purple or brown. The flesh also ranges in color from white to yellow, orange, or orange-red. 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. It is the ‘soft’ varieties that are often labeled as yams in the United States.
Why the confusion?
In the United States, firm varieties of sweet potatoes were produced before soft varieties. When soft varieties were first grown commercially, there was a need to differentiate between the two. African slaves had already been calling the ‘soft’ sweet potatoes ‘yams’ because they resembled the yams in Africa. Thus, ‘soft’ sweet potatoes were referred to as ‘yams’ to distinguish them from the ‘firm’ varieties.
Today the U.S. Department of Agriculture requires labels with the term ‘yam’ to be accompanied by the term ‘sweet potato.’ Unless you specifically search for yams, which are usually found in an international market, you are probably eating sweet potatoes!
Sweet Potato pie is a southern classic. For this tasty version of a Yam Pie, use sweet potatoes or yams!
- 1 piecrust
- 2 medium size yams (or sweet potatoes) boiled in their skins until fork tender. (about 20 minutes)
- ¼ cup butter
- 1 cup sugar
- ½ cup milk
- 1 egg
- 1 teaspoon vanilla
- ½ teaspoon ground nutmeg
- Pinch of salt
1. Using your favorite piecrust, roll out and fit into a 9-inch pie pan. Set aside.
2. Peel yams. (This is easy if you immerse the yams in cold water right after boiling. The skins will slip right off.) Mash yams with softened butter until smooth and creamy. Mix in sugar and milk, add egg and beat briefly with a fork to blend. Stir in vanilla, nutmeg and salt. Pour into pie shell.
3. Bake on center rack in a 400 degree oven for 30-35 minutes, until pastry is nicely browned and filling seems set around the edges. Cool to room temperature before cutting.