A Comprehensive Guide to Unagi

Whether you are a connoisseur of all things related to Japanese cuisine or an occasional consumer or even if you have never tried Japanese food before, you may have come across an ingredient known as Unagi. Have you ever wondered about the preparation process for Unagi before consumption? I can tell you that it is a very intriguing. Read on to discover Unagi’s preparation process for consumption.

What is Unagi?

Unagi is the Japanese name for the freshwater eel that can be found in Japan ,China, Korea, Vietnam and the Philippines. A little known fact about these mysterious sea creatures is that these freshwater eels leave their freshwater habitat and head to the sea to reproduce. It is also worth noting that aspects of their reproductive cycle are still mysterious to scientists. This is due to the difficulty that comes with observing their reproductive patterns in  the ocean.

Can you eat Unagi Raw?

We now move on to the topic of the preparation process for Unagi before consumption. Some may assume that Unagi can be eaten raw. However Unagi is always cooked. There is a very good reason for this. That reason is that uncooked Unagi is poisonous due to a neurotoxin found in its blood. As such, Unagi has to be cooked spectacularly well before they are fit to be consumed by anyone.

Unagi Kabayaki Preparation

One way of cooking Unagi is as follows:

  1. The Unagi fillet is steamed for a few minutes to make the meat tender. This is traditionally done in a wooden steamer.
  2. It is then grilled.
  3. Intermittently during the grilling process the Unagi is dipped in a tare sauce (a sauce that contains soya sauce, oyster sauce,sake and mirin).
  4. The Unagi is grilled until its exterior is brown and crisp while the inside of the Unagi is soft and fine.
  5. After the Unagi has been cooked properly and has the desired texture, consistency and dark brown colour, it is now ready to be eaten. You can consume it on its own or with noodles, rice or any other accompanying dish that you think would compliment Unagi.

 Diversity in preparation methods: A tale of two regions

Japan is very well known for its varied regional cuisine. That diversity applies to the way Unagi is prepared in different parts of Japan too. For example in Eastern Japan/ Kanto steaming is part of the preparation procedure for Unagi. In Western Japan/Kansai however, Unagi is not steamed but is grilled until it is really really crispy. 

Another difference between the Kansai and Kanto regions lies in the way Unagi is cut. In the Kanto region, eels were split open from the back while in places in the Kansai region such as Osaka the Unagi eels were cut through the stomach. It is said that one reason why this variation exists can be traced to the Edo period of Japanese history. At that time restaurateurs in Tokyo (then called Edo), cut their Unagi in this way to not remind their customers, particularly samurai of Seppuku. Seppuku was a ritual form of suicide that was typically practiced by the samurai class of Japanese society. It is truly amazing that a very nuanced history exists behind Unagi preparation. This makes it fascinating and unique.

Where can you find Unagi?

Unagi are found in the wild. Nevertheless, a lot of these eels are farm raised for consumption. In terms of where you can buy Unagi, you can purchase it from stores that specialise in selling Japanese groceries.

Unagi farming in Japan

As mentioned earlier, it is possible to raise Unagi in farms. Let us take a look at the farming process for Unagi with specific attention to Unagi farming in Japan:

The process of Unagi farming in Japan

  • Young Unagi also known as Glass Eels are caught from rivers or along coastlines between November to April to be farm raised. Fishermen do this by sweeping them up from the sea or river through the use of fishing nets. When fishing for young Unagi in rivers, fixed nets are used. On nights when there is a new moon, hand nets are used to scoop up young Unagi that are attracted to the moonlight.
  • After the young Unagi have been caught they are then moved to ponds within aquaculture farms and are raised for  a time period that ranges from six months to 18 months depending on the farming method, which can be single year farming or multi year farming.
  • When young Unagi are first brought to aquaculture farms they typically weigh about 0.2 grams. Their length measures up to 6 centimetres.
  • In the case of young Unagi being raised by the single year farming method, they reach market size when they have been raised for six months. These Unagi tend to weigh between 200 to 300 grams. This weight range is a key signifier that young Unagi has attained market size.
  • Due to the fact that July is the month where demand for Unagi is significant, the single year farming method is used to cater to the market demand by raising young Unagi that have been caught between November to January.
  • As for Unagi that are raised using the multi year farming method, they are typically caught in the time period of February to either March or April and raised on farms for a period of 18 months.
  • Once the Unagi are ready to be distributed to consumers they are checked to see if their size is consistent.
  • After the screening process is complete, the Unagi are brought to preparation areas. They are then placed in tub shaped containers with holes that facilitate water flow. The Unagi are kept in these containers for 2 days before being shipped live to Kabayaki restaurants, processing plants etc. where they are then turned into various kinds of food products.
  • Another important aspect of Unagi farming is the maintenance of a consistent water temperature of 28 degrees Celsius in the farming ponds. This helps to ensure that they grow well.
  • This temperature is maintained thanks to the clear plastic insulation that roofs the Unagi farms.
  • As for the feed that these young Unagi eat, it is made from fish meal and is combined with water. This concoction is given to the Unagi in the form of a paste. 

Unagi farming in China

Some aspects of Unagi farming in China

Another country that engages in Unagi farming to a significant extent is the People’s Republic of China. Let us explore some aspects of how they farm Unagi:

  • Young Unagi/Glass Eels are caught along the coasts of China and then brought to farms to be raised.
  • Traditionally the young Unagi are raised in earthen ponds within farms in the China. The size of these ponds measure about 3000 to 5000 metres squared with a depth of about 1 to 2 metres. 
  • In terms of the duration taken to raise the young Unagi it is the same as what was mentioned in the earlier section.
  • Once the eels have attained maturity and can be sold they will be transported to the processing plants of different distributors where they are treated in ice slurry and processed to make a variety of different Unagi based food products including Unagi Kabayaki.


Which countries are major producers of farmed Unagi?

Let us now move on to discuss which countries are major producers of farmed Unagi. They include the People’s Republic of China, Taiwan, Japan and Korea to name a few countries. Significantly, the People’s Republic of China has become a major producer of farmed Unagi. An example of this is visible in how 73 percent of global production of farmed Unagi in the year 2003 came from the People’s Republic of China that amounted to 146 217.54 tonnes out of a total global production of 200 298 tonnes.

Which countries are major consumers of farmed Unagi?

Countries that are major consumers of farmed Unagi include Japan, the People’s Republic of China, South Korea, Southeast Asian and European countries. Japan is the largest consumer of Unagi. It is notable that East Asian countries are major consumers of Unagi. One reason for this is proximity to the habitat of Unagi. Another reason is Unagi playing a major role in their cuisine. Examples of this include Japanese and Korean cuisine. To put things into perspective, it has been reported that South Korea consumes about 10 000 to 13 000 tonnes of Unagi annually. A significant statistic indeed.

What about wild caught Unagi?

Besides being farm raised, Unagi are also directly caught in the wild. This is significantly the case in Japan which is one of the countries that make up the habitat of Unagi. Yet due to a variety of factors, the population of wild Unagi has dwindled significantly. As such catching Unagi in the wild has significantly reduced in recent years. As an example, based on statistics from the Food and Agriculture Association of the United Nations (FAO for short) the number of wild caught Unagi has been steadily dwindling. This can be due to population decline as well as measures to help maintain the sustainability of Unagi through fishing restrictions in countries such as Japan.

Some foods that include Unagi

Let us now look at some popular dishes in Japanese cuisine that include Unagi as an ingredient.

Some popular that have Unagi as part of their ingredients include:

  • Unaju: This is a dish that has grilled Unagi on rice presented in a layered box called a Jubako and is accompanied with soup. The combination of the Jubako and Unagi is the basis for the Japanese portmanteau Unaju that is the dish’s name.
  • Unadon: Unadon is similar to Unaju. However it is different because it is served in a bowl that is commonly used to serve Donburi dishes. The usage of a rice bowl and the Unagi are the reasons for the dish’s Japanese name Unadon. Unadon literally means “freshwater eel bowl”.
  • Unagi Nigiri: Another dish that uses Unagi that you might have heard of if you’ve visited sushi restaurants is Unagi Nigiri. The name of this sushi literally means Unagi sushi (The word Nigiri is another name for sushi in Japanese). This sushi variety is served with a piece of Unagi wrapped on top of sushi rice with seaweed.

The taste of Unagi

Unagi has a subtle sweet taste. This makes it a potential darling for people who like food with a sweet flavour profile. Some people also say that Unagi tastes similar to that of catfish. (Let us know if you agree). Whatever the case may be, one thing is clear. The combination of the Tare sauce and the Unagi meat is a truly potent culinary teamup.

The texture of Unagi

Another aspect to Unagi that adds to its intriguing gastronomic profile is the texture of the ingredient. It has a very chewy slightly slippery texture. This makes for an engaging experience when it comes to chewing it in your mouth. This due to the fact that it enables you to experience the flavour for quite a long time. This enhances your exploration of Unagi’s flavour profile for a longer time because you have to slowly savour its flavour. All this culminates in a very different kind of gastronomic experience with Unagi.

A sobering reality to remember

 As seen through our observations, Unagi plays a major role in Japanese cuisine. Furthermore, it is often a favourite with customers who patronise Japanese restaurants all over the world. However do keep a sobering reality in mind. There are some factors that are affecting the future sustainability of Unagi as a food source. Let’s look at some possible factors that could be affecting them. Overfishing has impacted the population of the Japanese eel very badly. Moreover there is a study implying that changes in the ocean currents could also affect the Unagi reproductive cycle. These are some factors that negatively impact the sustainability of the Japanese freshwater eel. As such mindfulness must always come into play when it comes to our consumption habits in regards to Unagi.

Attaining a deeper sense of understanding

Hopefully, thanks to this guide, you have attained a deeper sense of understanding about Unagi and gained a deeper appreciation for it. Moreover, I hope that the importance of responsible food consumption was brought to your attention through the lens of what is happening to Unagi as a food source. All in all, I hope that you have found this whole journey to be an enlightening experience. Till next time, take care and keep widening your intellectual horizons be it in regards to food or any other topic that may interest you.

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