Shonan Ninomiya Charcoal Baking Club for Our Hometown 湘南二宮ふるさと炭焼き会 was established in 2000, just like Lovers of Niiharu Citizen Forest 新治市民の森愛護会. The reason why volunteers came for the Ninomiya Club was similar to Niiharu’s. Already at that time, the landlords of the area could not manage their land and forests by themselves. The abandoned forests, together with golf clubs in the area, contributed to the worsening of a water stream, called Kuzugawa River 葛川 powering to Sagami Bay. There was a call for action, and people responded for forest management. The difference between them and Niiharu is, their activity is programmed around charcoal cooking schedule, and they make not only bamboo charcoal but also wood charcoal. Accordingly, their charcoal kiln is traditional and fully built BIG one. They harvest logs during summer, and let the logs to dry. Immediately after chopped down during May to September, logs contain on average roughly 56% of moisture. Volunteers wait until that number goes down to around 35% in winter, which has higher possibility to yield charcoals of better quality.
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| Charcoal baking hut for Ninomiya Club |
Their field is in the north east of Ninomiya Town 二宮町, called Isshiki Community 一色. We took (whichever) Kanachu Bus from Bus stop #2 in the North Exit of JR Ninomiya Station 二宮駅. After about 20 minutes’ bus ride, we got off at Midorigaoka Nishi Stop 緑が丘西. From there a quiet farm road continued for about 15 minutes’ walk. It was a tranquil and idyllic place surrounded by forest and veggie fields. Almost at the end of the veggie fields, there was their charcoal hut. The place is ideal for volunteers to bake wood charcoal. It takes time to cook wood charcoal so that people must come to see how it is going even in dead winter night. This place is far enough for smoke not to reach residential area, but near enough for volunteers in town to drive to check the kiln at 22:00.
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| #2 Bus Stop in the North Exit
of JR Ninomiya Station. Please take whichever bus from here to Ninomiya Charcoal Club. |
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| Charcoal Baking Hut, this way |
Until petrol completed world domination in the late 1950s, Japanese ordinary people used wood charcoals for household activity, such as cooking and heating. Providing business environment for sufficient charcoal supply of satisfactory quality was VERY important for Japanese government. Academics for agricultural science engaged in policy-oriented studies to bake charcoals as much efficiently as possible. Among them was Prof. Ihachiro Miura 三浦伊八郎 for Tokyo University (during 1912-1952). He tried numerous designs of kiln, and proposed Miura-style Charcoal Kiln. Japanese government employed and generalized his idea as the “standard design of charcoal kiln.” Between the 1930s and the 1950s, the Office promoted it all over Japan, together with a “standard manual for baking charcoal in forest.” To this day, this standardization remains. So, there is “Prefectural recommendation for the length of time to fire the kiln to cook wood charcoal,” which I mentioned last week. The kiln of Ninomiya Club is followed the historical and still-official spec, professionally made by a builder from Tanzawa Area. It’s 300cm*270cm*120cm solid structure of concrete and firebricks. In the blueprint, it looks like a uterus. Inside, we really can feel like “In Utero.” (Er, no, Nirvana was not suitable for background music there, I tell you.) The recommended product life of this type of kiln was about 10 years. Granted Ninomiya Club uses it during winter only. Besides, there are not many professionals anymore in Japan who can repair and rebuild such early 20th century technology. The volunteers use the facility with care. They check the kiln continuously, and if there is a small crack, they mend it immediately. The kiln still goes strong.
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| In Utero |
For preparation, first they cover the dirt floor inside with halved bamboos. Bamboos facilitate the volunteers to work inside the kiln, and become buffer protecting material logs from complete combustion when the entire structure is heated up. Next, volunteers pack the kiln by vertically lining up logs harvested and cut for the height of the kiln during summer forestry. In order to prevent the logs from being burned to ashes, the kiln must be packed as much as possible. The Club cooks many kinds of trees from the forest, but the majority of them are sawtooth oak (Quercus acutissima) and jolchan oak (Quercus serrata). Especially, sawtooth oak of ∅15cm or so is the most treasured material. It becomes a beautiful charcoal called Kikusumi whose cut end has numerous small cracks concentrically spreading, like a flower of chrysanthemum. Japanese tea ceremony loves it, and so, it can fetch 10 times more price than the ordinary wood charcoal. Working inside the kiln is strangely calming. Yes, we have to move very heavy logs, and let them stand as vertical as possible. It’s a heavy work, but there is something very gentle. In-Utero effect? The gaps between the logs, and the logs and the ceiling/wall of the kiln are filled with “remnants” of woods that come during sizing process of logs for the kiln. For one operation in their kiln of Kanagawa standard, they pack 2t of charcoal material and 900kg of “remnants.” This yields roughly 300kg of wood charcoal, i.e. 16% of return, which is Japanese average, more or less.
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| Empty kiln |
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| Harvested and dried logs are
cut to the proper size for kiln with this machine. |
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| Bamboos are lined for the floor. |
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| Many kinds of trees are prepared to be cooked. |
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| The materials are standing in this way. |
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| Remnants are packed above the materials. |
They stop stuffing the ingredients 1m behind the mouth of the kiln. From there, the volunteers pack “remnants” logs to the opening, and close the kiln with simply stacked refractory bricks and a concrete panel. A space between the bricks and the panel is intentionally made. It is the space for fire logs are placed. At the end of the kiln, there is an opening for removable chimney. Here, they install the chimney and an industrial thermometer that measures the temperature of smokes. From the numbers, the Club infers the temperature inside the kiln. To bake the wood charcoals, they make fire in the space between the bricks and the concrete, and measure the temperature at the chimney. When it reaches to 85°C, it’s the sign the materials for charcoal has started self-combustion, they stop feeding the fire logs and semi-close the mouth of the kiln to feed fresh oxygen that promotes thermal self-decomposition of cellulose, lignin, et al. From the start of firing logs to this stage, it takes about 8 hours, they say. It’s more or less the same as Niiharu’s bamboo charcoal baking. The difference starts here.
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| A diagram when the kiln is heated. Red lines and arrows show how the heat circulates inside the kiln. |
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| Piling up the bricks … |
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| The front of the kiln is ready for firing up. |
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| The space between the bricks
and the concrete panel. Tinder is thrown in. |
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| The vent at the end of the kiln |
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| Cray soil is harvested nearby
to concoct mud to shut the structure. |
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| Chimney made of cast metal is
attached to the vent. |
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| The foot of the chimney is sealed by the mud. |
In Niiharu, we wait 4-5 hours more after half-closure, then shut the kiln completely with refractory bricks, concrete panel, and mud. It’s one-day operation of roughly 17 hours. For wood charcoal to be made, this time schedule is too short. So, Ninomiya people kept unsealing the kiln for roughly 68 hours, on average. Unlike bamboos, the wooden logs inside need this much time to complete thermal decomposition. You may say by burning firewood more before semi-closing the opening it will let temperature of inside climb faster, and so, the process can be more efficient. OK, if a charcoal maker takes this approach, (1) more materials can be burnt to ashes inside so that the yield becomes lower, and (2) the texture of final products becomes more fragile so that the amount of calorie one unit of charcoal can create is lower, i.e. bad quality charcoal. The point is, we have to heat the kiln not too fast in order for the logs to turn into a structurally smooth charcoal. To make it possible, the kiln continues spewing the smoke for 4 consecutive days, and the charcoal baker must attend the kiln for 4 days more or less incessantly. We cannot do it in the middle of urban megalopolis, you know.
About 68 hours later, the temperature of the smoke arrives to about 320°C. The volunteers shut off the smoke coming out from inside by stacking at the opening of the kiln more refractory bricks and sealing them with mud. They then remove the chimney and close the exhaust port completely with iron lid and mud. The kiln will be left as such for at least 7 days or more until the interior cools down completely to the outside temperature. My senior forest volunteer cheerfully told us his experience while he checked the temperature at 22:00 in pitch black forest. “You see, I could figure out something big was moving around at the back of the charcoal baking hut. It then oinked and showed an intention to running towards me! I kindled the firewood more, which may have shown the boar it was not an appropriate direction to proceed. That was a close call.” Woooooooow. It seems to me their forest does not have homes for bears or deer. Yet, boars, racoon dogs, and the other animals are moving around especially during nights around the hut. Cold winter night, starry sky, quiet but jolly world of living creatures in forests … It sounds like in utero. I wish I can experience it someday …
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| The chimney leads the
smoke this way outside. During charcoal cooking, empty bins are located at the end of the chimney to collect wood vinegar. The Club distills it and sell it to the neighbor. They have regular customers who makes reservation to get it. |
The baked charcoals by Ninomiya Charcoal Baking Club is available in Ninomiya Tourism Association in a building next to Ninomiya Town Hall. The product is also used for BBQ at Shonan Beach Seines for tourists. In normal years, the events are held during March to November, RSVP (for more info, this aggregator can be of some help). Now, no one knows when we can return to the normal schedule on beach … but eventually, we can taste charcoal-grilled sardines and crams again. Let’s be patient.
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| In utero |
If you find a problem in Yokohama’s North
Forests, please make a contact with
Office for the Park
Greeneries in the North 北部公園緑地事務所
Yokohama Municipal Government
Creative Environment Policy Bureau 横浜市環境創造局
Phone: 045-311-2016
FAX: 045-316-8420
657 Nanasawa, Atsugi City, 243-0121
〒243－0121 厚木市七沢657
Phone: 046-248-0323
You can send an
enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/
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