I've been wanting to discus the venerable sweet potato for quite a while. Having read Chilies to Chocolate: Food the Americas Gave to the World and History of Food I've been curious about the confusion surrounding sweet potatoes. I've also wanted to learn a bit more about them and see if there were difference between the available varieties.
In the last 100 years there's been a trend to shrink the genetic biodiversity of our food resulting in less choice. After growing tomatoes and many herbs I have become well aware that you grow food so you can have the right food, not necessarily to save money. It is cheaper to grow your own but if you factor in your labor a garden you probably costs you twice as much as just buying the food but the advantage is better quality and more choice. There are paste tomatoes, slicing tomatoes and sauce tomatoes depending on your needs. There are many different varieties of mint (chocolate mint is very nice), basil and other herbs. You can grow pumpkins for Halloween and pumpkins to eat (not the same thing, see my previous articles on pumpkins). However, we're nearing a disaster of epidemic proportions. Not only are we engineering seeds that can't produce more seeds and then patenting them so other people can't grow food without paying for the seeds but the plants can't survive without us making them subject to our commercial interests. There are seed banks trying to combat this but that will only allow us to plant these various crops, it won't give anyone the incentive to do it.
We are narrowing our biodiversity for commercial profit. It's just easier to grow and ship two types of tomatoes than 10. Likewise it's easier to provide one type of basil, one type of mint, one type of sage etc... Another reason may be that people are just further removed from their food than they once were so we don't pay attention to the different types of foods we have available. If you've never studied sweet potatoes you may think there's only one type – labeled Sweet Potatoes in the store. In fact there are over 6,500 varieties of sweet potatoes. Obviously we can't try them all so I focused on the three varieties commonly available in super markets – Beauregard, Garnet and Jersey. I've seen the Jewel variety in stores too on occasion but they weren't available for this comparison so I may do a follow up when I can find some.
I tested three varieties cooked in 4 different ways and noted the difference. Before you skip the rest of the article because you think they're all the same you might want to reconsider. Read the article after the jump.
What's the difference between a Yam and Sweet Potato?
There is a lot of confusion surrounding naming conventions of the sweet potato. You'll probably see more sweet potatoes labeled Yams than labeled Sweet Potatoes. There's some history behind that which I've written about before so I won't spend too much time reiterating but they're all sweet potatoes in America unless you dug them up at an International grocery store. I won't go into details because I have other articles that discuss this but I'll explain briefly. Yams are a root grown in Africa, Sweet Potatoes are a completely non-related tuber of the same family as the Morning Glory flower and originate from the Americas. There are NO commercial crops of Yams in America. Early on most sweet potatoes grown in America were the Yellow firm variety. Later when farmers in Louisiana started growing sweet potatoes they chose the Puerto Rican soft orange variety. To avoid confusion (and only to cause it for the next 100 years) they used what the African slaves called the sweet potato nyam or Yam. The Wolof word nyam ironically refers to the real Yam from Africa which the slaves were familiar with. Also the varieties grown in Louisiana tend to be of the soft category. So in short if it's orange and soft and from Louisiana it may be called a Yam but if it's from anywhere else, yellow and firm it's probably called a Sweet Potato but be sure they're all sweet potatoes. The confusion has been great enough that the USDA requires the name sweet potato on every can or box of sweet potatoes even if they're marketed as Yams. Look closely and you'll find it.
Interestingly enough I bought a bag of “Yams” for this review and they didn't list their variety on them but they did have the name of the farm (AV Thomas Produce) and upon contacting them they seem to be at least as confused as consumers. From my experience shopping at farmer's markets I've learned that you can ask a grower how to keep a plant alive, how to grow it and when to harvest but don't expect them to tell you what the plant is good for or anything else as they might not know. They grow things, they're not botanists or chefs. Here's their answer.
“What's the difference between a sweet potato and a yam? Honestly, it depends on who you ask. Botanists, archaeologists, geneticists and even linguists give different answers, because different vegetables have been called either sweet potatoes or yams at different times in history or in different parts of the world. In the United States, it’s easier. “Sweet potato” is the broad category name, and yams are a type of sweet potato. So all yams can also be called sweet potatoes, but not all sweet potatoes can be called yams.)”
Actually AV Thomas, all those folks agree especially the botanists and geneticists. The linguists will tell you that some sweet potatoes are called yams but they won't tell you they are yams because that's not their field of study. I digress. From this point forward we're going to call them all sweet potatoes since that's what they are from a botanical standpoint. Yam is just a marketing name.
Categorizing Sweet Potatoes
There's really two ways of categorizing sweet potatoes that's reasonably important – color and firmness. The sweet potato called Yam is generally an orange fleshed soft sweet potato of either Puerto Rican, Jewel or Beauregard varieties. The one labeled Sweet Potato is usually yellow fleshed, firm and commonly of the Jersey variety. Although some orange varieties can also be firm like the Garnet but I'll get to that in a moment. As a rule of thumb if it's orange someone will slap the Yam name on it.
I was able to find three varieties – Garnet (labeled Garnet Yams), Beauregard (labeled “Yams”) and Jersey (labeled Sweet Potatoes). The naming is so inconsistent that I had to do some research to find out which was which. You'll see later that just because a sweet potato is orange doesn't mean it will taste or act like another one that's orange.
After Louisiana started growing Puerto Rican sweet potatoes they moved on to the Jewel but just 25 years ago the Louisiana State University bred a new variety that had great yields and was disease resistant. They named it after the French-Louisiana Confederate General Pierre Gustave Toutant Beauregard – Beauregard for short. They've since engineered a new one called the Evangeline which is supposed to carry on those traits but is sweeter. I wasn't able to find any of these nor do I remember ever seeing them in stores.
Beauregard Sweet Potatoes have copper skin and orange flesh and are soft tubers with medium sweetness. Beauregard is now the largest crop of sweet potatoes in America so if you get a bag like mine that only says “Yams” then Beauregard is probably what you're looking at. So far every grocery store I've checked has had Beauregard sweet potatoes.
Garnet Sweet Potatoes have deep red or purplish skin and with dark orange flesh. These are firm potatoes with very little sweetness. Mine were labeled “Garnet Yams” and I've been able to source them at about 3 grocery stores locally.
Jersey Sweet Potatoes are your traditional yellow sweet potato. They have a golden yellow skin that fades to tan when stored. It has dry mealy yellow flesh. These are firm sweet potatoes with a high sugar content. I've been able to find these at all grocery stores.
How I tested:
I cooked each 4 different ways – Julienned and sautéed in butter, julienned and baked, julienned and deep fried in vegetable oil and for the fourth test - baked whole in the oven. The first three tests were to see which one made the best sweet potato fries. I added the sautéed in butter method after seeing it mentioned on several websites. The last test shows which one would be better baked whole without any foreign flavors. I was thinking of adding tests for soups etc. but I think when it comes to soup the flavor element is most important, any difference in texture would disappear if cooked until soft enough to puree.
Test 1: Julienned and sautéed in butter
This test was added based on the number of recipes online that raved about it.
Only tasted butter. What's interesting about this is in other tests the Garnet by far had the strongest flavor but when sautéed their own flavor just vaporized and all that was left was the flavor of melted butter. I wonder if the dryness of this potato makes it a sponge and/or perhaps the loose structure of the proteins allows for the butter to cling. Garnets tend to be a more fibrous potato that may possibly lend to this. It's just a theory though. They ended up being soggy too. Color was bright orange.
Soggy like the Garnet but doesn't taste like butter as much. The texture of a Beauregard is smoother making me think the protein fibers are closer together and possibly not absorbing as much butter (or it has higher water content). Again just a theory. They had a nice balanced mix of sweet potato flavor and butter. They did tend to fall apart though so slicing them larger would be a good idea. Color was a bit brighter orange than the Garnet.
Browned quickly, turned a bit crispy due to hight sugar content. Turned soggy like the others after sitting but had very little noticeable butter flavor. This was not the expected behavior at all. After you eat them a while you can taste the butter but only slightly. It's almost like the potato's flavor in some way cancels out the flavor of the butter. Color was pale yellow with noticeable browning.
Test 2: Julienned and deep fried
Naturally the traditional way of making a sweet potato fry hence the name.
THE sweet potato to fry because it holds up under the fryer. When you buy sweet potato fries in a restaurant this is undoubtedly what you're getting. The center of the fry is fairly smooth and soft, outside crisp. Very strong savory flavor, not sweet at all. This would be great for dipping in sauces and for a less sweet experience. Remember that the Garnet is a firm sweet potato so it naturally has more rigidity but I also wonder if I was able to keep them in the fryer longer because they didn't burn due to the low sugar content. Color was bright orange.
Flavor is good, texture not so good, turns to mush. I did an extra batch which I cut into larger pieces to keep them from turning to mush which failed miserably. Stayed limp and didn't crisp up. I tried larger slices and cooked them longer which made no difference. So it would be easy to chalk these up to being a sweet potato fry failure but if you don't mind soggy limp fries they're actually an enjoyable experience. Mild sweetness and very smooth texture. I preferred this flavor over the Garnet but I don't think a restaurant would ever serve them because customers would send them back just on texture alone and ask that they be “cooked longer”. My other tasters also liked them as long as they looked beyond the texture. Color was a bit brighter orange than the Garnet.
Good texture, crisped up like a Russet or Yukon would but had a bit more “fibrous chew”. When you take a bite the fry likes to hold on a bit whereas a traditional French fry would sever easily. Taste wasn't that much different than a regular French fry but with a bit more of a root flavor. I think if someone were preoccupied and served Jersey sweet potatoes they may eat them without noticing. However, if you stop and think about the flavor they're stronger than a traditional fry (which to be honest doesn't taste like much) and may even have more in common with a fried parsnip than the other sweet potatoes here. The flavor at first seemed “off” and unpleasant at first but after eating a few they start to grow on you like that quirky cousin you had as a kid. Having said that these still got eaten last. Color was yellow.
Test 3: Julienned and baked
By baking julienned sweet potatoes I was trying to find a less fat soaked way of making sweet potatoes. I followed some online advice that said to coat the pan with oil, cook the sweet potatoes at fairly high heat until done then drop the temperature down to 225 degrees and leave them in for another 20 minutes to firm them up.
Again very savory flavor. A bit fibrous and a little tough. Didn't turn crunchy though and remained limp.
Shrunk quite a lot making me think they contain more water which would explain why they didn't absorb as much butter in test number 1. Maybe need to bake some larger slices next time to combat this. Flavor was still very nice. A bit mushy and definitely limp.
Turned to crunch. Browned. Nothing wrong with the flavor but not very strong. You'd have to eat a handful to figure out what they tasted like. Still they grow on you. They do not taste like the other two at all and are the only ones that crisped up like a traditional potato French fry.
Test 4: Baked whole
Going into test four I was ready to declare Beauregard the winner based on it's nice smooth texture, mild sweetness and balanced flavor. However, an upset happened. I baked all three at the same temperature until a fork could be slid into them easily.
What a surprise! The firm fibrous sweet potato comes from behind to win. The garnets were done cooking a full 10 minutes before the others. Color darkened and “grayed” quite a bit. Not as appealing to look at. In fact I had to blind fold my testers when I suspected they were choosing Beauregard based on color and not flavor. After being blind folded one changed their vote to Garnet just showing how much of an influence visuals are. The Garnet had the strongest flavor in the other tests and I really expected it to be too dry and savory when baked but something magical happened. It came out reasonably moist (perhaps because it's meat softened earliest so I pulled it from the oven first) and the flavor although strongest tempered somewhat and became pleasant. Texture was still a bit too fibrous to be pretty. Probably not the baked sweet potato served in restaurants just out of looks.
I was sure the Beauregard would open a can of hurt on the other two here but that wasn't the case. It's good points were a very bright orange color and smooth creamy texture. However, it got soundly trounced by the Garnet in the flavor department. Ask me why and I can't tell you. Still not a bad baked sweet potato experience and you know people will think it tastes better than it does based on looks alone. The “go to” sweet potato if presentation is important to you. I wonder if you were to serve mashed sweet potatoes and mixed Beauregard and Garnet 50/50 if you wouldn't have a winner in both departments. Next time.
The Jersey was dense, pale and lacked any sort of desirable flavor. I really don't think this is the sweet potato for you if you're baking them.
Garnet (labeled Garnet Yam)
Overall a much stronger savory taste. Shocks you a bit. Also much drier than the others. Good structure but a bit fibrous. Great for making fries and great baked. Not good sautéed in butter.
Beauregard (labeled Yam)
Overall very nice flavor. Smooth texture. Like a Garnet but not so savory and much smoother. Doesn't stand up to any sort of stress, turns to mush. Very bright color under any situation. Decent for fries, good baked and looks great.
Jersey (labeled Sweet Potato)
Overall – very different flavor from the others. More “root-ish” with a hint of parsnip. Supposedly sweeter which I didn't really find in the flavor but did notice it in how it cooked. Always the first to “caramelize” in the pan, in the oven etc.. Browned in the fryer. To be honest I'm not sure what these are for. I guess I'd not use them in the same recipes as the other two but rather wherever I'd use root vegetables like parsnips.
I was really quite surprised at how different each acted and it became quite clear that you don't just grab the nearest sweet potato for every recipe just like you wouldn't grab a red potato when Russet is needed. The inconsistent naming conventions became a point of frustration. I feel like I'm barking up the same tree over and over but considering how DIFFERENT all three were there really needs to be better categorizing at the store level. Today I stopped by a fifth grocery store to check their supply and they had a bin full of Jewel and Beauregard sweet potatoes mixed together (which is not a huge infraction because they're very similar sweet potatoes). Next to it was a bin full of Garnets and about 6 or 8 Beauregard mixed in which don't behave at all like each other. Either the produce folks don't know the difference and put them wherever they feel like, the grower doesn't know the difference or customers keep putting their produce back in the wrong spots. Maybe all three. Before I did this research I wouldn't have cared because I didn't know the difference either.
However, from now on I'll be buying Garnets to bake for me, Beauregards to bake for everyone else, Beauregard for fries for me and Garnets for fries for everyone else. I'm really curious about taking equal amounts of Garnets and Beauregard to make mashed sweet potatoes from. I'm also now more curious about which makes the best soup since the flavor win went to Garnets but the color win went to Beauregard.
Another conclusion about fries. If you're going to make sweet potato fries put them in a vat of hot oil. All other methods seem to be a waste of time. If you're worried about health issues perhaps you should try different oils, do the double temp method that Cook's Illustrated discovered, don't overcook them, drain them well, or just eat fewer fried sweet potato fries. But honestly there's probably a million other places you could cut fat from your diet. Had a sandwich lately with mayonnaise on it? Congealed fat right there. So my advice is to just toss them in the fryer and enjoy.