This time of year, autumn, is harvest season. In Western countries, mainly in North America, Britain and Ireland, the pumpkin is one of the most symbolic crops of the autumn harvest because it represents Halloween. In Japan, there are other crops, but the sweet potato is one of the most popular. It is popular, because it is flavoursome and, at the same time, affordable – unlike a genuine Japanese Matsutake mushroom, another autumn dainty, that costs as much as Kobe Beef!
There is a Japanese saying, ‘Imo, Tako, Nankin’ – a sweet potato, octopus and a squash. This is from a line in Ukiyo Zoshi, or Tales of the Floating World, by Saikaku Ihara (1642-1693), a Japanese poet and a novelist in the early Edo Period. In this tale, Ihara describes these three items as foods that women adore. (The sweet crops could be easily understood, but why octopus? Many Japanese women love it, but I wonder if this affinity is the same in other countries where octopus is eaten.)
The original line, to be precise, is actually ‘Shibai (plays), Joruri (a form of traditional Japanese narrative music accompanied by a Shamisen or Samisen, a Japanese three-string musical instrument), Imo, Tako, Nankin’. However, the first two items have since been dropped from the line, and saying now emphasises only their appetite for these three foods!
Today I will introduce an easy-to-make and yet tasty Japanese snack made of sweet potatoes, which is not only the favourite of women, but also the general populace: Daigaku Imo, which literally translates to ‘university potato’.
Why is this snack named after a university? There are some interesting and dubious anecdotes on this: About 80 years ago, a student/s (not clear if one or more) at the University of Tokyo, one of the best national universities, made and sold the snack for his/their tuition. Another story, which is more likely, dating back to about 100 years ago, is that there used to be a shop selling steamed sweet potatoes near the university, and when they started to sell a variety coated with syrup, it became popular amongst the student body.
Anyway, what is Daigaku Imo like? I discovered that ’candied sweet potato’ exists in Western countries and ’basi di qua’ in Chinese dishes. But even though the former describes the Japanese snack and the latter looks similar, but both are quite different from Daigaku Imo, which is crispy, yet soft and moist inside. More precisely, the sweet potato snack is deep fried and caramel-coated. Here is the recipe. Enjoy!
600g sweet potatoes
vegetable oil for frying
[syrup to coat sweet potato pieces] Try B if Shoyu and Mirin are available!
A: Plain 90g sugar 4 tbsp (60ml) water
B: Authentic 4 tbsp sugar 4 tbsp Mirin 2 tbsp water
2 tbsp Shoyu, or Japanese soy sauce
1 tsp black sesame seeds (optional)
- Scrub the sweet potatoes very well and cut into rolling wedges or chunks. (leave the red skin on for colour)
- Leave the pieces in water for about 10 mins. Drain and dry with a towel or paper.
(optional: leave in water with 1 tbsp salt for 30 mins. Drain and dry in the sun for half a day or microwave (600W) for 2 mins. The salt brings out sweetness and the sun-drying helps to make them ‘crispy, yet soft and moist inside’.)
- Heat the oil in a large/deep pan till around 150C and fry until softened.
- Take the potato pieces out of the oil once and then fry again in 180C oil until lightly browned. This will make them crispy.
- For syrup, mix A or B in a pan over medium-low heat. Stir the mixture until completely melted. Bring to a boil and simmer without stirring until thickened and lightly golden brown.
- Put the pieces into the syrup, and mix and toss until well coated.
- Sprinkle with black sesame seeds.
They are best served warm, but be careful – both the potato pieces and the syrup are very hot!!
(The article, first contributed to a newsletter in 2012, was revised and posted on 23rd September 2015.)