Tuesday, March 06, 2007

I Yam What I Yam...

When I was a child I thought the only way to eat a yam was with marshmallows and lots of brown sugar. I dreaded this dish passed at Thanksgiving. That casserole dish of orange whipped goo.

I love baked sweet potatoes and have often wondered about the different varieties. Is a yam different than a sweet potato?

There is no botanical difference between a "yam" and a "sweet potato". In fact, they are both sweet potatoes. "Yams" are simply a type of sweet potato and were given that name to distinguish them from other types of "sweet potatoes".

There are three features that distinguish "yams" from other sweet potatoes: its skin color, flesh color and moisture content of the potato.

Here are some general characteristics of each:

Sweet Potatoes

Skin: Sweet potatoes are usually lighter in color than yams. Color ranges from light yellow or tan. The exception to this rule is the Japanese sweet potato, which has a deep purple skin, but meets the other characteristics of sweet potatoes.

Flesh color: Light yellow to pale orange.

Moisture: Drier than a "yam" and somewhat sweeter.


Skin: Deep red, purplish or dark copper tone.

Flesh color: Deep or vivid orange.

Moisture: Quite moist; almost "mushy". Not as sweet as sweet potatoes.

For a taste test, I picked up three different varieties at the market(listed in photo order top to bottom): "Kotobuki" (or Japanese Sweet Potato), a Jersey (or plain sweet potato) and a Garnet (a "Sweet Yam").

I found the Japanese variety more dry than a traditional sweet potato. The flesh is a light colored and more dense than a traditional sweet potato.

The "Jersey" is my favorite variety and also the classic sweet yam everyone knows of as a sweet potato. This is the variety that is longer and skinner that the other varieties that have the same traditional orange on the inside. It is a moist and soft potato. I love this variety cooked as fries or plain. Delicious and nutritious.

The "Garnet" was good. It is more like a regular potato than a sweet one. It has a light skin with a light yellow inside. If you are craving a sweet potato than this one will disappoint. If you want to try a different variety, this one is delicious. I think it would be a great alternate to use for making mashed potatoes. The flavor reminds me of spaghetti squash. Not as sweet as the squash but similar nonetheless.



Anonymous Brian Glass said...

Actually, a yam and sweet potato each belong to a different genus. A yam belongs to the genus dioscorea while a sweet potato belongs to the genus ipomoea.

Most if not all yams labeled as such in the United States are actually sweet potatoes.


7:18 AM  
Anonymous Erika Haub said...

I once read about a study conducted among a tribal people in Africa where the rate of conceiving twins was extremely high. The researchers noted a relationship between high yam consumption (this was the staple food item among this tribe) and having twins. Anyway, thought it was an interesting side note to your story!

11:36 AM  
Blogger Fer said...

While they are from two different genera, which is botanically correct, in the US they are distributed as one group. Any botanical difference between the two is complicated further by the fact that the USDA requires both names to appear on labels. This practice began when the producers and shippers needed a way to distinguish the white flesh types from the orange.

The more you research this the more confusing it gets! Thsnks for your info.

9:15 PM  
Blogger Fer said...

That is a fascinating fact! I want to know more about that.

9:16 PM  
Blogger makarios said...

I'm not sure if this is common elsewhere, but from my part of the world, we have lots of yam desserts that are de-lish.... like yam ice cream, yam-cream with gingko nuts (orh-ni), yam bubble tea, yam ice-shake, yam-cream biscuits, yam-flavoured bread and buns, yam sticky-glutinous rice balls... :) I love yam.

7:48 AM  
Blogger Fer said...

Makarios-Wow. All of those items sound amazing. Yam ice cream? What does that taste like? What spices are used? I love bubble tea but I have never had yam boba! Lucky!

9:27 PM  
Blogger myscint0 said...

I'm sorry to say you are quite wrong on the yams and sweet potatos being the same thing. In the United states, Sweet potatos are labled as yams and Sweet potatos because of the different types of sweet potatos and differences in colors. A true yam is a Root. A good website to show the difference is from the capital of sweet potatos, North Carolina :) http://www.ncsweetpotatoes.com/index.php?option=com_content&task=view&id=89&Itemid=230

Theres plenty of info at this site if you are interested!

8:46 AM  
Anonymous Mike Robinson said...

Mike Robinsonsweet potatoes are the orange potatoes that many Americans eat at Thanksgiving. They are usually grown in the southeastern U.S. Yams do not grow in the U.S. because they are a tropical crop. Yams come in many colors but are often white.

9:32 PM  

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