What’s the difference between yams and sweet potatoes?

StealthToad@lemmy.world to No Stupid Questions@lemmy.world – 150 points –

Boss and former coworker got into a very amusing argument over this and it got me curious.

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The name "yam" is used for a few different root vegetables.

The word is from West Africa and refers originally to Dioscorea yams, which are found in many parts of the world — having been independently domesticated in Africa, Asia, and the Americas. The word "yam" is related to the Fulani word for "to eat", and was introduced into European languages by way of Portuguese colonizers.

But in the US, "yam" almost always refers to a variety of sweet-potato (Ipomoea genus), which is more closely related to a morning-glory flower than to either Dioscorea or a true potato (which is a Solanum nightshade).

Both sweet-potatoes and potatoes are native to the Americas. Sweet-potatoes probably were grown first in the Yucatán or in eastern South America, while true potatoes are from Peru and western South America.

Meanwhile in New Zealand, a "yam" is oca, an Oxalis species — close relatives of sourgrass and redwood sorrel. And in Malaysia, "yam" is taro root!

The word “yam” is related to the Fulani word for “to eat"

The etymology is a bit messy. It might be from Fula, but it's probably from Wolof ⟨ñàmbi⟩. Nowadays the Wolof word means yucca, but given that yucca is from the Americas, odds are that it was originally used for any edible root; or potentially another local root.

Either way (from Fula or Wolof), the word ended in Portuguese as ⟨inhame⟩ [iɲɐ̃.me]. Nowadays it refers to taro, but before that English borrowed ⟨inhame⟩ as ⟨yam⟩.

Nowadays the Wolof word means yucca, but given that yucca is from the Americas, odds are that it was originally used for any edible root; or potentially another local root.

That reminds me of how the word "corn" referred to any grain until maize was discovered

Yup, it's the same underlying phenomenon - as maize becomes the prototypical non-wheat cereal grain for plenty speakers, they eventually repurpose the word "corn" to mean exclusively "maize". (British dialects are the exception that prove the rule, as maize isn't so prevalent in the islands.)

This doesn't happen just with crops, mind you - even animals get this treatment. Guarani "jagua" for example went from "hunting beast, specially jaguar" to "dog", while Navajo "łį́į́ʼ" went from "pet, livestock, specially dog" to "horse".

I see. So it's a little bit like how in the U.S. pickles refers to pickled cucumbers, but in other places pickles can refer to other pickled foods. Yams are to sweet potatoes what pickles are to pickled cucumbers.

Another fun layer I've encountered recently has been "pickles" referring to a specific variety of (non-pickled) cucumbers that are usually used for pickling. So pickles are pickled pickles.

That's totally pickled.

Where has that video disappeared?

Gherkins are pickled cucumbers originally. Now Gherkins are the name used by brands in the US for the baby pickles.

Neat, so yams in the US refer to a sweet potato? Slightly related, but can you also explain the difference between Ube and Taro? I've had this conversation with my friends as well.

Yeah, if you go to a general US grocery store and see something described as a "yam" it's going to be a sweet-potato, usually a larger or starchier variety.

Ube is a Dioscorea yam native to Asia. It's closely related to the African yam. Most of this family of plants are big terrestrial vines that can live in somewhat dry places.

Taro, or kalo in Hawaiian, is from a different family of plants. It's related to the peace lily. Most of this family of plants live in aquatic or marshy places.

And now do kūmara! They sometimes get called sweet potatoes in New Zealand

Looking them up, it sounds like they're the same species as American sweet-potato, which is one more bit of evidence for early contact between Polynesians and South America.

I believe they are different. Kumala (in Fijian) is very different than a yam. Yams and uvi are more tubular, and the skin will slip off after cooking and kumala is more bulbous. Google shows different pictures than what I remember, showing kumala closer to taro (dalo in Fijian).

yams and sweet potatoes are not the same. Yams have rough, dark brown skin that is often compared to tree bark, and their flesh is dry and starchy like a regular potato. Sweet potatoes have smooth reddish skin, softer flesh (when cooked), and a sweet flavor.

source

It seems so obvious yet there is still so much confusion in the US

Our cans of sweet potatoes have an alternate label on the back that says yams, so apparently not much. (This is in the USA)

You have sweet potato's in cans? That sounds awful.are they pre-cooked? I don't understand why?

They're primarily used in as an ingredient. Often they are suspended in a sweet syrup and are thoroughly mashed to make a pie filling, it's actually not bad.

They’re quicker for making sweet potato pie since they’re already cooked. You add plenty of other ingredients to the filling so there’s less difference in the final product between canned and fresh

Why do we use them interchangeably for a casserole dish, but always say sweet potato pie - never yam pie? Sounds weird. Same with fries.

“Yam” doesn’t roll off the tongue as beautifully or sound nearly as appetizing

That still doesn't make sense, if you're making a fresh pie but using canned ingredients, you might as well buy a pie. I'm sure they taste OK, but sweet potato's are on of the easiest things to cook, if you want them soft before you put them in the pie, put them in a microwave for a bit.

USA has thanksgiving in a can, Christmas dinner in a can, even SPAM in a can.

Other places have SPAM not in a can?

yeah it says they're yams, but they have no relation to yams at all

Is that the reason the other guy is now a former coworker?

She is going through some rough shit and couldn’t work here anymore, but her and boss have been friends for years.

Sweet potatoes makes your fart smell.

Yams do not.

Source: my (unfortunate) experience in forbidden lands