I Yam So Confused! The Difference Between Two Commonly Mislabeled 'Tubers'

Q. What’s the difference between a sweet potato and a yam? 

A. About ten cents a pound. 

Ba dum.

Last year, I got into a friendly argument with a colleague at work about the difference between the sweet potato and yam. I didn't think there was a difference and I stood my ground. He disagreed, describing the yam pretty vividly. But he was a man whose wife (I'm sure) did most of their food shopping as do I, so what could he possibly know?

It turns out I was wrong. There is a difference but one that is made more confusing by the U.S.

Department of Agriculture which requires that the label “yam” always be accompanied with the words “sweet potato” when referring to a sweet potato. No wonder I was confused!

The sweet potato is a yellow or orange 'tuber' (a kind of elongated root vegetable). The yellow sweet potato has a thin skin and is not sweet despite the name. When cooked, it has a texture similar to the white baked potato. The orange variety (often called "yam" in error) has a thick, dark orange-reddish skin with orange flesh. It is sweet and moist. I used this variety for my recipe.

The yam

A true yam is the 'tuber' of a tropical plant and is not related to the sweet potato at all. The yam is a popular vegetable in Latin American and the Caribbean with many varieties available. The yam is sweeter than than the sweet potato and can grow over seven feet in length. The skin is brown or black skin and off-white, purple or red flesh, depending on the variety. 

Now that that's settled, I came across a recipe last week that I made on Sunday. The recipe called for a whole sweet potato topped with caramelized onions and parmigiano-reggiano This is almost to easy too post but it's such a nutritious side dish loaded with beta-carotene, an antitoxident that helps prevent heart disease and cancer. I changed up the recipe not being a huge fan of onions  and served mine with sauteed spinach (even more carotene!) and of course the tasty Italian cheese. 

Tonight, I sliced the leftover sweet potato and added it to my salad. Did I call this a side dish? It could really be a main course! 

Baked Sweet Potatoes With 

Caramelized Onions and 

Shaved Parmigiano-Reggiano

Ingredients

6 medium sweet potatoes

1 tablespoon unsalted butter

4 large yellow onions cut in half, then sliced into 1/2 inch thick half-moons

(OR substitute 3 cups of fresh spinach, steamed with 2 tablespoons olive oil added when cooked)

3 tablespoons sugar

I teaspoon kosher salt

1/4 teaspoon pepper

2 tablespoons balsamic vinegar

1/2 cup freshly shaved parmigiano-reggiano cheese

Directions

• Preheat oven to 450 degrees
• Place potatoes on a baking sheet for 45 minutes.
• For caramelized onions:  Melt butter in non-stick fry pan over medium heat. Add onions and cook until soft. Add sugar, salt and pepper. Cook on low heat for about an hour until they become caramelized adding small amounts of water if needed. Add vinegar and stir.
• For spinach: Steam spinach leaves until tender. Drain and dry as much as possible. Place spinach in saute pan and olive oil. Salt and pepper to taste.
• When potatoes are done, split open and top with onions or spinach and cheese.

The sweet potato