Mike covered most of the basics about the binchotan charcoal in this blog here.This blog goes much deeper into detail, its for the BinchoNerd's among us.
The Binchotan(備長炭) is named after a charcoal maker in Tanabe, Wakayama prefecture,BicchuyaChozaemon (備中屋長左衛門) who started to selling this type of charcoal (Tan or炭) in late 17th Century. Wakayama prefecture was called Kishu before the Meiji restoration in 1868 so the binchotan produced in the area is called Kishu Binchotan to differentiate from other binchotan varieties. Originally Binchotan was only from Wakayama, but some charcoal makers have moved to other areas in Japan like Tosa and even further to Miyazaki (Hyuga) seeking a specific type of wood called Ubame Kashi or Ubame Oak (ウバメ樫).
Ubame oak is harder, with a tighter grain than regular oak trees and is prefered by Binchotan charcoal makers. The areas that these charcoal manufacturers are located are all on a similar latitude and have similar landscape as Ubame oak usually grows in hilly and hard to reach areas, which makes harvesting this type of wood more challenging than regular oak.
Ubame can be written in several different kanji, usually either 姥目 (elderly woman’s eye) or 馬目 (Horse's eye) these are in reference to the buds of the trees that like wrinkly eyes.
I don’t know about you, but I’ve always been curious about the process of making charcoal. When I burn wood in a fire pit, all I end up with is ashes rather than charcoal. When I heard that to make charcoal the oak is burned at 1000 degrees centigrade, I thought everything would just to burn into ashes. The key to not letting that happen is oxygen, or rather, the lack of it. When you burn wood in an open environment, oxygen in the air will bond with carbon in wood creating CO2 and wood will burn down to ashes, but if you limit the oxygen when burning, it will take H2O out from the wood — resulting in charcoal! Binchotan and other charcoals are made in similar procedures — except for the final process, which we will get to later…
Any industry that relies on nature has to be careful of how much to take, because over harvesting/felling would threaten their industry. The same, of course, can be said to Binchotan makers. They rely almost 100% on natural resources. They have learned over the years just how much they can fell per year to protect the forest and industry. Although, with recent increase in demand for Binchotan, sadly, some companies have ignored their ecological traditions and have harvested more trees than they can recover so there is a threat to this particular wood for Binchotan. We are happy to say that our supplier remains committed to sustainable harvesting.
The first step to making charcoal is of course getting into the forest and chopping down trees. As mentioned above, these Ubame oak prefers to grown in hilly area so it is quite difficult to fell. Once the binchotan maker has enough wood, they will bundle it up. This is all done by hand due to the terrain. Also, the trees do not grow straight — so in order to comfortably bundle up the wood, they need to make incisions into trees and put wooden wedges into them to make them straight. Thicker trees are splitted in half. It’s a lot of work.
These bundles then go into a special kiln, layered in an upright position very neatly and tightly. These kilns are big enough for a person to walk into. Once they’ve layered the wood in, they add fuel wood that isn’t as dense, and burns more quickly. They light it and close the opening with brick and mortar gradually over 9 hours. As they are closed these openings are turned into 4 small holes. Two at the top of the kiln and two at the bottom, for air flow to the fire and to release steam. Let it burn low and slow with very little air flow in order to take the moisture out of the wood for 6-7 days. During this process white steam comes up from the chimney. Once all the steam is gone, the wood has become charcoal.
From here, regular charcoal is made by closing all the openings in order to snuff the fire out by starving it of oxygen. If all they wanted was regular charcoal then they could let it cool down and remove the charcoal, but Binchotan goes through an extra step. This step is what makes Binchotan special.
It’s called “Seiren” 精錬, or refining. A Binchotan maker, instead of closing the opening to snuff out the fire, will make more openings into the kiln, gradually adding more air flow. This process has to be done at very gradual pace. A rapid air flow inside of the kiln would burn everything into ashes, and too slow will not make this process as effective as it should be. The process takes between 24 to 48 hours, during which the inside temperature reaches 1000 degrees centigrade. This process burns off bark and makes the charcoal denser, tighter, harder, and more pure carbon. In fact, Binchotan charcoal is 95% or more of pure carbon, where regular charcoals are around 75%.
The Binchotan maker then starts to take hot charcoal out of kiln. But! If they do the same process as regular charcoal making (extinguishing by starving the fire), by the time the kiln cools, all that would be left in the kiln is ashes. They have to empty the kiln while the coals are hot. As they take it out of the kiln, they cover the Binchotan with sand and ashes to cool them down gradually. The dust that coats the charcoal is the reason why Binchotan is called “white charcoal”.
The whole process takes up to 10 days and produces about only 600kg of Binchotan per batch. Much material is lost in the process. The weight of the charcoal at the end is one tenth the wood that goes in, not to mention the wood burned as kiln fuel. Binchotan making requires much skill, and is a very labour intensive process that has been passed down generations. It’s our honour to bring the product of these traditions to our customers in Canada.
If you’d like to see the process for yourself here are links to great videos from our Binchotan supplier, Okazaki-san. They are quite long (6 videos and they are about 20min. each) and have no English subtitles, but now that you’ve read this article, we bet you’d get some enjoyment out of seeing it all happen.
Here is the Video Number 6! Go checkout the first 5! Here.