Sweet Potatoes vs Yams – What’s The Difference?

mashed sweet potatoes (or yams) with butter

Looking forward to yams this Thanksgiving?

Well I’ve got a Turkey Day side dish alert for you – chances are those yams you’ll be digging into are actually sweet potatoes!

What?

It’s true, sweet potatoes have been masquerading as yams for years!

Is this all just a case of mistaken identity? Or is there something more nefarious going on here?

Well, we did a little digging; here’s what we learned…

Two Peas In A Pod? Uh, No.

You might think yams and sweet potatoes are a lot alike.

Both are root vegetables loaded with healthy nutrients and enjoyed around the world.

Baked, boiled, roasted, fried – both yams and sweet potatoes can be cooked an almost endless number of ways and served up either savory or sweet.

Sweet potatoes need to be harvested by hand.

Unlike traditional white potatoes, sweet potatoes are usually harvested by hand because they scrape and bruise easily.

So sure, yams and sweet potatoes may have a few things in common – but biologically, these two tubers are worlds apart.

And in fact, their physical characteristics are so different, it’s pretty easy to tell genuine yams and sweet potatoes apart with just a quick glance!

Let’s take a closer look at each …

Sweet Potatoes – Tubers For Your Sweet Tooth

Known as Ipomoea batatas to science nerds, these are the sweet potatoes Americans are most familiar with.

And let’s clear one thing up right now: Sweet potatoes are not technically potatoes. All the common spuds you know and love like russet, red, white, fingerlings, and others belong to the nightshade family.

Sweet potatoes hail from a completely different family tree – the Convolvulaceae, better known as the “morning glory” family of plants.

A sweet potato vs yams comparison: Here's a Hannah sweet potato on the left, and a Jewel sweet potato on the right.

Both of these are actually sweet potatoes. That’s a Hannah variety with the off-white flesh on the left, and a Jewel sweet potato on the right.

Most sweet potato varieties (there are around 400) have at least one tapered end and a fairly smooth surface. Skin colors can be white, yellow, red, copper and even purple.

Here are the two types of sweet potatoes you’re most likely to find at your local grocery store:

1. Golden-colored skin with a firm flesh inside that’s either a light yellow or a creamy white. This sweet potato remains fairly firm after cooking (more like a white or russet potato) and with a somewhat drier and kind of waxy texture. Common varieties here include Hannah and O’Henry. Grocers often just label these “white sweet potatoes.”

2. Darker, copper-brownish skin with a soft flesh that ranges from a light shade of orange to a darker, red-orange color. Sweet taste with a soft-silky texture, these sweet potatoes are very moist when cooked. Some of the popular varieties you’ve probably seen in your grocer bins include Jewel, Garnet, Beauregard, and Covington. Supermarkets often label these orange-fleshed tubers as either “sweet potatoes” or “yams” or a combination of both.

Yams – Roots In Africa and Asia

These are the real thing. Authentic yams.

The scientific name for these beauties: Dioscorea.

No relation to traditional potatoes or sweet potatoes at all.

Yams come from yet another big, happy plant family, the Dioscoreacae – their closest kin include lilies and grasses.

Real yams imported from Africa

Cultivated yams are historically tied to Africa and Asia, but are now grown in Latin America, the Caribbean, and other tropical regions. Any true yams that show up in specialty stores in the USA are likely imported.

There are some 600 varieties of yams that grow in a very wide range of sizes and shapes, with skin and pulp colors that are equally diverse. Some can reach lengths of five feet or more and tip the scales at over 100 lbs. One of the most commonly cultivated and distributed yams is easy to distinguish just by its dark (brown or black) skin that feels very rough and scaly – almost like tree bark.

Compared to sweet potatoes, yams are generally less sweet, contain more starch, and are a bit drier than sweet potatoes.

So those are just some of the distinguishing characteristics of true yams.

Don’t sound familiar to you?

That’s probably because you’ve never had a real yam before.

Which also means the bright orange root veggies you’ve been eating all this time are actually sweet potatoes and not really yams!

So Why Are My Store’s Sweet Potatoes Labeled “Yams”?

How in the world did sweet potatoes come to be called “yams” when they’re not even remotely close to the real deal?

The answer is here, in a two-part tale that spans centuries and continents …

Part one: Back in colonial times, enslaved Africans transported to America called the sweet potatoes grown here “nyami” because the tuber reminded them of the taste and texture of their native yams. That West African word was shortened to just “yam” and gradually became an acceptable descriptor for sweet potatoes in the New World.

Part two: Thanks to some old school selective plant breeding back in the 1930s, agriculturalists at Louisiana State University came up with a new sweet potato they were really proud of. It was a bright orange cultivar from a Puerto Rican tuber. So bright, they thought, that it made rival sweet potatoes grown in Maryland, Virginia, and New Jersey look pale in comparison. This sweet potato, the scientists surmised, deserved a completely new name. So LSU lobbied the U.S. Department of Agriculture for a name change. What did they want to call them? You guessed it: “Yams.” The USDA said okay, but with the proviso the newly-christened yams would also be labeled as “sweet potatoes.”

So that’s how the term “yams” came to be associated with just about every orange sweet potato you see in U.S. grocery bins today.

You Say Potato, I Say Yam…

Well what’s in a name, right?

At the end of the day, it doesn’t really matter that much whether sweet potatoes sometimes get mistaken for yams or vice versa.

What counts is that no matter how they are cooked, orange sweet potatoes packed with vital nutrients and filling fiber will continue to be a great choice for healthy diets like paleo.

And as a bonus, sweet potatoes (aka yams) are pretty sweet to have around during the holidays, wouldn’t you say? Especially when prepared with a little extra love and shared around the table with family and friends.

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