IZUMI's World of Japanese Peppermint
★和泉研究室 総合案内★
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北見ハッカと心理ゲームのちょっぴりマニアックな世界･･･
 A unique combination of chemistry and psychology...

　★Scene of Traditional Mint distillation in Nikoro-cho, Kitami City

 
 

Traditional Distillation of Japanese Peppermint
-introduction with movies-

★Introducing the October 2021 coverage in movie clips with a relaxing talk between Mitsunori Izumi* and Tomoko Takechi**! Please come and enjoy the tradiotional distillation method.
 
for any questions or comments, please email me to izumi@tokai.ac.jp .
 
*Professor, Tokai University.
**School Counselor.
 

hello everyone.

  We introduce the traditional mint distillation scene with movie clips, observed in Nikoro town in October 2021. Read, watch and enjoy the process of steam distillation, which began in Hokkaido's pioneering era and disappeared around the end of the 20th century..
(Photo: Kaoryanse Park in Kitami City)
 　The method of separating an essential oil from japanese peppermint grass, which has been used by farmers since the Taisho era, is the steam distillation method. This is a common method of getting essential oils from various plants whitch involves blowing steam into dried grass to evaporate the oil. It is said that distillation was carried out all day and night in a distillation shed jointly owned by multiple farmers. The unrefined raw essential oil obtained here is called "torioroshi" oil. This was the end of the work by the farmers, and the extracted raw oil was packed in bottles or cans and shipped. Then torioroshi-oil was, at factories of mint manufacturing company, L-menthol crystal was separated and refined crystals and oils were sold in Japan and overseas.
    Since the KITAMI PEPPERMINT FACTORY was constructed in 1933, most of the unloaded oil has been contracted to the factory, and the oil has been shipped under the "HOKUREN" brand, and its high-quality HOKUREN products have been highly praised around the world.
  
    Now in the 21st century, while we hardly see distillation sernery of those days, there still retains the vestiges of those days in Nikoro town and we can see traditional distillation every autumn at the distillery hut behind the Information Center in Nikoro Hakka Park in Nikoro-cho, Kitami City.
    A distillation apparatus called the "Tanaka style" is located here, and on October 7, 2021, when we visited, one company was working on distillation, and two days later, the NPO "Nikoro Kaori no Sato" had started distilling.

    On this page, through video footage, we introduce the distillation process for obtaining an essential oil from dried Hakka (japanese peppermint) grass. Please enjoy! 
 
 
☆Mint distillation in the early 20th century☆ 
    Please take a look at each process of distillation that took place in the distillation shed, which is located behind "Nikkoro."
     This time I observed hard workers all day from morning to evening. Whereas, back when this area was covered in peppermint fields, farmers kept fires burning throughout the day and night for days.
    Photo 1 is a shot of the distillation shed from the back. You can see that a extraction chamber is placed in the center of the hut. Behind the door on the right is the boiler room, and the steam generated here is carried through pipes under the floor to be blown into the chamber.
    Around 7 a.m., the fire was already set with hay packed the day before, and after about three hours of distillation, before noon, the fire was turned off, then the steamed residue was taken out, and hay was packed for the second distillation.
 
    I rearranged this series of work steps in the following order: [Packing the grass into the kiln] -> [Start of distillation] -> [End of post-distillation] -> [Remove the steamed dregs].
 
    Please read and see the following explanations.

 Photo 1
(Click to watch the video)
 
 
 
(1) Preparation of hay 
    The cultivated and harvested mint grass is dried in the sun using a method called “Hasagake” (Photo 2; hakka field next to Nikoro Hakka Park).
    When you visit "Kaoryanse Park" in Kitami City, you can see the growth of Hakka (japanese peppermint) from spring to autumn, the autumn harvest, and this "Hasagake". Please come and visit us!

 Photo 2
(Click to watch the video)
    It takes about 1 to 2 weeks to dry. It is best to have a slight amount of moisture left when filling the extract chamber.
    The dried grass is unloaded from the wooden frames, packed into iron baskets, and transported to the shed by a tractor (Photos 3 and 4).
 
 Photo 3～4
(Click to watch the video)
 
 

 

(2) Preparation for Distillation 
    Meanwhile, preparations inside the hut are also progressing. The chamber used here is called the "Tanaka style," the cover of which can be lifted up using a pulley (Photo 5). The video explains what a pulley looks like and its role.
 
Photo 5
(Click to watch the video)
 
    Let's compare Nikoro's distillation equipment with that of the Kitami Mint Memorial Museum, the stainless-steel equipment in demonstration every day (Photo 6).
    Steam generated in the boiler (A) is blown from the bottom of the extraction chamber (B) filled with hay, passes through the introduction pipe (C) and the snake pipe (D), where it is cooled by water and condensed, finally drops into the water/oil separator (E).
    By the time it enters the separator, it has already separated into water and oil. Due to the difference in density, yo'll see an oil layer (upper layer) and a water layer (lower layer). Only the upper oil layer can be easily extracted.
 
Photo 6
(Click to watch the video)
    If you look at the body lifted up, you can see a hole in the center of the floor where steam generated by the boiler blows up (Photo 7).
    On top of that, circular net with casters is placed as a pedestal, and the main body is placed (Photo 8).
Photo 7～8
(Click to watch the video)
 
 

 

(3) Loading hay into the chamber 
    Finally, the hay transported by tractor is loaded into the extraction chamber (Photo 9).
    At that time, if the packing is uneven and there are gaps inside, water vapor will pass through the space and the distillation efficiency decreases, so They need to firmly and carefully tamp down with your feet. This process of swallowing up two baskets of grass took nearly 30 minutes during this interview, and seemed to be quite hard work.
    Once the filling is complete, wrap a towel around the edge of the chamber as a gasket, cover the lid, and secure tightly the main body with a nut (Photo 10).
 
Photo 9～10
(Click to watch the video)
 
 
 
 
(4) Work after Distillation 
    During this visit, distillation took about 3 to 4 hours, but the distillation time is not set previously, each time distillation continues until not much oil comes out.
    During distillation, white steam leaks from the small gaps between the chamber, floor, and lid, creating an atmospheric distillation scene. You can fully enjoy the unique aroma of Hakka distillation, but the only way to experience it is by going to the place and smell. (Photo 11).
    The amount of oil, floating on the distilled water flowing out of the snake pipe, gradually decreases as the distillation time progresses, so occasionally scoop it out with a ladle and visually check the amount of oil. Distillation ends when the oil is reduced (Photo 12).
    When  they determine that the process is complete, the boiler is stopped, the obtained oil (hakka essential oil) is taken out into cans, and then bottled (Photo 13).
Photo 11～13
(Click to watch the video)
    When distillation is complete, remove the connecting tube and open the lid (Photo 14).
    At this time, we are enveloped in a large amount of steam and the unique aroma of the distillation. (This is the most impressive moment, and you can only experience it if you are there. I highly recommend you experience it there!!)
    After that, the cover of the chamber is lifted using a pulley, and the steamed dregs are pulled out on the pedestal (Photo 15).
    They are transported using a wheel loader and loaded onto a light truck (Photo 16).
(This steamed dregs is plowed into the fields and reused as fertilizer.)
Photo 14～16
(Click to watch the video)
    In addition, during this interview, we were able to see the work after the distillation, held every day at the Kitami Mint Memorial Museum. We were able to capture very valuable footage.
    In the case of the stainless steel distillation equipment at the Museum, the steamed grass is lifted out of the body of the chamber. We have also made a video of this process, so please take a look (Photo 17).
    The steamed residue produced here is also used as fertilizer by cutting the large branches into short lengths with scissors and plowing them into the thin grain field in front of the museum.
 
Photo 17
(Click to watch the video)
 
 
 
 
 

Conclusion

    The date of distillation of Hakka differs every year depending on the day of harvest and drying, so it was difficult to know in advance and it was difficult to capture. This was achieved for the first time through the exchange of information between co-researcher, Ms. Tomoko Takechi. Since only one equipment is used by multiple groups in turn, it is natural that the start date and number of days required for distillation will vary depending on the amount of harvest for each group. This time, the distillation schedule in Nikoro town was changed two days before departure, and I could flexibly change the schedule accordingly, without changing or canceling rental car dates, changing requests for on-campus business trips, or procedures for canceling or absenting classes if there are classes or meetings on the same day. I could stay in Kitami without changing my business trip schedule and I was fortunate to be able to observe the operations by two groups. Through this experience, I felt that, on this reporting trip, I experienced a sense of laxity that modern people, who are accustomed to following a strict schedule, tend to lose sight of. It was a very human experience, and at the same time, I felt that this kind of relaxed feeling was also connected to the future that the people of Japan are aiming for as a new way of working in the coming era.

    In addition, the Mentha Memorial Museum also informed me that I could meet drying scenery held at Kaoranse Park, which is about a 10-minute drive away, and I also met with the Pearson Society's administrative staff. I was able to do an interview with the director and was kindly shown around KITAMINT HALL the next day. In their very kind response, I felt a real sense of humanity in the kind hospitality that was on a different level than the work. This is because I feel that the scent of mint, which created the "world's champion" scent in Hokkaido during the Taisho and Showa eras, is still remained in people's unconscious minds even now, even in Heisei and Reiwa. As a reporter, I would like to continue reporting on the past, present, and future of Kitami Hakka and the people surrounding it.

 
 
 
 

Acknowledgment

During this visit, we received detailed explanations and information from NPO "Kaori no Sato", Kitami Hakka Holdings, Kitami Mint Memorial Museum, NPO Pearson Association, and Plains Country Information Center ("Nikkoro"). I would like to express my sincere gratitude to all of you.

*This research was supported by the 2021 Japan Educational Aid Association of Walfare Foundation.
 
 
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