Daigaku Imo - Japanese University Sweet Potatoes

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In the fall, many universities throughout Japan have big festivals called 大学祭　daigaku-sai, meaning university festival, or 文化祭　bunnkasai, Culture Festival. They are basically street fairs held on campus, with lots of food and fun stalls, concerts, even ghost houses and amusement rides. Many of the big ones also hold concerts in which top Japanese singers and bands appear. Daigaku Imo, which means University Potato, are candies sweet potatoes, a sweet and slightly savory snack that is often served at university festivals in Tokyo.

The snack itself probably originated as a cheap, calorie-rich, affordable snack sold to cash-poor students around universities in Tokyo around the turn of the 20th century. The idea for deep frying and then sugar coating potatoes most likely came from similar snacks in Chinese cuisine.

Daigaku imo is simple to make, yet a bit tricky. You ideally want to coat the sweet potato slices completely with a hard caramel sugar coating, but too often the sugar gets crystallized. It doesn't taste bad when it does, but it looks far better with a shiny, smooth coating. I've found the best way to accomplish this is to make a fresh batch of the sugar coating for each batch of potatoes cooked. This is not diet food by any means, but regardless, to me they are one of the main treats of fall.

Recipe: Daigaku Imo

Ideally you want to use Japanese-type sweet potatoes, which have a pink-purple skin and white flesh (see how they look like). You can use the orange-fleshed kind if that's all you can get a hold of.

1 sweet potato makes enough for 2 to 4 people, depending on appetites, though I've seen the whole lot disappear into one mouth quite quickly too.

  • 1 medium sweet potato
  • Oil for frying
  • 2 Tbs. white sugar
  • 1 Tbs. sugar syrup (see notes)
  • 1/2 tsp. soy sauce
  • Gomashio (sesame salt) - homemade recipe

Scrub the sweet potato very well. Cut the sweet potato into wedges, leaving the skin on for color (you can peel it if you want). Put the cut pieces into cold water.

Heat up about an inch or so (3 cm) of oil in a large pan, or use a deep fat fryer. Drain and pat dry the sweet potato pieces, and put into the hot oil. Fry on medium heat until cooked through and lightly browned.

In the meantime, mix up the sugar, syrup, and soy sauce in a small pan over medium heat, until the mixture is completely melted and very syrupy. Take off the heat.

Take the potato pieces out of the oil, drain and immediately put the piping hot pieces into the sugar syrup mixture. Be careful - both the potatoes and sugar are very hot! Mix and toss to cat the potato slices. Sprinkle with some gomashio.　Separate the potato pieces so they don't get stuck to each other.

They are best served warm, though are still tasty when cold.

To make more, just repeat the whole process, making the sugar syrup mixture fresh each time as the potatoes cook.

I know you are going to ask...

...if you can you oven-bake the potato piees instead of deep frying them. Well you could, but the potatoes won't have the piping hot surface to which the sugar syrup mixture adheres to, forming the caramel coating, and the potato pieces will probably turn limp. However, the flavor will still be good, so if you're deep-frying phobic by all means bake your potato pieces, coated in a little oil or butter.

Notes about sugar syrup

Using part sugar syrup and part sugar helps to make a that fine, brittle caramel coating that is desirable. In Japan you would use 水飴　(mizuame), but different parts of the world seem to have different forms of sugar syrup. In the U.S. use corn syrup. In England, golden syrup will do. Molasses is a possiblity, though it will affect the flavor a lot. You can also try it with just sugar (use 3 Tbs.), though this may result in crystallization. It will still taste good though.

Submitted by maki on 2008-10-22 15:29.
Filed under:  dessert japanese fall vegan gluten-free party snack

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Comments

china

22 October, 2008 - 17:36

it may not be worth mentioning, but there's a similar holiday dish in texas. we call them "candied" sweet potatoes but it's a lot the same, we toss sweet potatoes (the southern kind which are orange) in brown sugar and bake them until they caramelize and turn kind of hard and shiny. it's oven baked but it's not limp, though there's some syrupy bits at the bottom it gets a hard, candy texture on top.

maki

23 October, 2008 - 13:41

Hmm, for some reason I never thought of just sprinkling on sugar...I always thought in terms of sugar syrup, which does seem to make baked potato bits go limp. I'll have to try the sugar-only! (though I wonder how adding the soy sauce, which is sort of critical for daigaku imo, would affect it...)

Madeline

24 October, 2008 - 09:08

What if you brushed the baking potatoes partway through the baking process with the soy and sugar glaze?

PlusQ

23 October, 2008 - 12:31

I've always wanted to make these type of sweet potatoes, since I found a box of seasonal Pocky that was Daigaku Imo flavored. I then had to look up the recipe because it looked good, but it was for a baked version. I never did make them and totally forgot about them till today. This time, I know I will.

Phil

23 October, 2008 - 19:27

i love this blog! i have to try this immediately :) sweet potatoes are my favorite! I wonder if I replace the traditional sweet potato casserole with this if it would upset people on the Thanksgiving table. I know most of my relatives in the US would freak out if there was no sweet potato casserole!

Hacques

24 October, 2008 - 04:06

Hai Maki,

I used to make something similar to this in Indonesia. Using the same red sweet potatoes, but we used special sugar, it's coconut brown sugar, called Gula Jawa.

We diced the potato, fry them, then melt the Gula Jawa. Lastly we throw the fried potato into the sugar. Unlike ordinary sugar, it won't get into caramel, but simply melt and stick perfectly within the potatoes.

By the way, your blog quite popular here, in Indonesia. There are many Japanese lover here and most of the people in the community knows well about this blog ^^

Good job, Maki-san.

anon.

25 October, 2008 - 03:00

今日は。初めまして。　makiさんの大学いも、おいしそうですね！
私も先月つくりましたが、日本のようなさつまいもがなかったので　アメリカのスィートポテトでつくってみました。サツマイモのようなほくほくした食感がなく水分がでてしまって失敗。。。次回はコリアンマートへ行ってサツマイモを買って作ってみます。

maki

29 October, 2008 - 11:59

こんにちは！　そうですね、オレンジ色のスイートポテトは水っぽくて大学いもには向いていないかもしれませんね。　

(to translate: The orange colored sweet potatoes, which are the most common kind in the U.S. and many areas of Europe, are a bit too watery to make great daigaku imo, in the opinion of two Japanese people here :))

jump☆art

29 October, 2008 - 03:59

Last week or so I went looking online for daigaku imo recipes!
I ate these all the time in Japan. I was vegan when I lived there and constantly snacked out on Muji-brand karintou, and daigaku imo from the "Izumiya" depaato in Kyoto. Very excited that you posted this, I'm gonna give it a try.

yunike

29 October, 2008 - 20:55

When I visited Japan earlier this month I ate this japanese sweet potatoes.
I thought that you use kind of honey for the syrup outside of them because the texture was so watery... not caramelized like when you use pure sugar. Thanks for this recipe, I'll try to make this later :)

Hanna Fushihara

8 November, 2008 - 17:34

Thank you for the recipe and for writing the blog! I am Japanese but have been living in the States so long that I can't read Japanese as well as I would like to and have such a hard time finding the things I want to make in English. Also thank you for the vegan recipes!!!!
Just made the daigaku imo and it was the perfect "Natsukashi- agi" that I remember.

brook

9 November, 2008 - 23:50

my husband and I lived in northern China as ESL teachers and ate this dish at least once a week at our favourite restaurant. Since we've been home I have tried to recreate it on my own with disappointing results. Thanks for giving me a jumping off point as the chinese version is a bit different. Have you ever heard of a similar dish only instead of sw. potatoes "scrambled" eggs are used? I have not had the guts to even try it even though we loved it. BTW I am currently bubbling nikujaga as I have the beginnings of a cold and think this will taste better than chicken soup! I am so glad I found your blog! Thanks!

anneakemi

1 January, 2009 - 01:29

I think this is a delicious dish. I tried to make it and when we ate some of it right after, it tasted great. However, by the next morning, the leftovers became soggy and the sugary coating was not hard anymore. Is there any way to ensure this doesn't happen? I'm wondering if I didn't store it right or if I didn't coat the potatoes right? Any advice?

karen

23 January, 2009 - 02:37

Iam taking a group of students to a sudoko/kakuro competition tommorrow. Part of the day will be spent learning about Japanese culture. We are expected to bring a Japanese dish to share. Lucky for me I found your blog and I am planning on bringing this dish! The problem is I never made it before and am required to prepare enough for 65 people to sample!! Any suggestions on how to make a large amount ahead of time? I am planning to use crock pots to keep the potatoes warm. Will this affect the coating?

maki

23 January, 2009 - 07:42

Putting them into crockpots will make them go soggy and limp. You don't have to keep them warm - they will be ok for a while at room temperature, though not too long. The only way I can think of to make a big amount of this is to just use multiple frying pots and make a big batch. I am sure I would have chosen this one to make for the first time for a big crowd...but...umm...Good luck!

Melissa

22 March, 2009 - 18:12

I made these for a girl's night with my friends. It was very good. I even made the homemade gomashio, which I'm going to use on my rice since I have some left over. Thanks for the recipe.

Noemie

23 April, 2009 - 04:45

I didn't have any kind of sugar syrup at home, so I replaced it by some maple syrup - il was delicious!
I have been searching for a long time for a Daigaku imo recipe and I really like this one!

Cand86

16 July, 2009 - 00:49

When I was in Japan, a friend once told us about, and later made what she called daigaku imo in her rice cooker . . . it was sweet, but didn't have any of the brittle caramel-y coating you describe here, and to my knowledge she didn't fry or bake the sweet potatoes otherwise- I had thought they were called "daigaku imo" because they were so simple to make if you only had a rice cooker (which ever college kid does, of course).

I wonder if it was a personally tweaked recipe?

maki

16 July, 2009 - 10:32

The recipe I gave is a more or less traditional daigaku imo recipe, so I think the version your friend made is a variation (since a rice cooker would steam cook the potatoes).

Melissa

29 October, 2009 - 03:14

Also, be careful if you eat persimmons or anything that takes a long time to digest before eating these sweet potatoes you could get an upset stomach. These potatoes are supposed to digest very quickly and anything obstructing that digestion can leave pretty sickly like it did for me last night.

Marian of the South

1 December, 2009 - 04:04

Ejee...I read about sweet potatoes in a manga (Fruits Basket, you know) and since I'm a food/cooking geek I was like "sounds good. Let's try it!". First I thougth they were sweetened common potatoes, but when I read some recipes it turns out they are actual sweet tuberous roots. So I was like "Shit. Please, may these 'sweet potatoes' thing exist in México..". I google it, went to Wikipedia, and guess what? here in México and Central America "sweet potato" goes by the name "camote".
I must tell you, I almost fell from my chair. Camote. One of the most common and ancient foods in my country. It was, I don't know, sort of a cultural shock: to see the camote (nahuatl word) be referenced as "sweet potato". It was kinda weird.
Anyway, now you know: if you ever come to México (or other Central America country) and want to cook some sweet potatoes, don't ask for "papas dulces", but "camotes". So far, I've only eat the purple variety, don't know if we grow the other ones. Oh, and camote pastries (empanadas de camote), are Heaven.

Porimoto

3 February, 2011 - 02:12

Hi Makiko, I ate these for the first time in Tokyo recently, and couldn't wait to make some when I got home to Australia. They are so delicious, and turned out perfectly, one of my diners commented that they were like vegetables and dessert all in one - so true!

ケイチイ

4 August, 2011 - 15:29

These are quite possibly the most amazing thing I've ever made. I used agave nectar for the sugar syrup and it turned out perfect. Thank you for the wonderful recipe!

Valerie

8 October, 2011 - 04:06

These are delicious! The glaze by itself is so sweet that it made my throat hurt, but I loved it on the potatoes.

cdd710

3 December, 2011 - 19:37

I have made this recipe many times and I always get a great reaction from people. I love it! Today I'll be trying it with mizuame for the first time, since I can finally buy it from Family Market in Astoria. In the past I always used brown rice syrup which was also delicious. Thanks for this wonderful recipe!