PRODUCTION IN KISHU REGION, WAKAYAMA PREFECTURE AND TOSA REGION, KOCHI PREFECTURE
Binchotan coals are activated coals produced in Japan's southern Wakayama Prefecture, or on the neighboring island of Shikoku in Kochi Prefecture. The term “activated” refers to a very specific manufacturing process: to make coals, of course, you have to burn wood, but obtaining activated coals is a much more complex operation. Details are given below.
Petite île à Wakayama - small island in Wakayama
Bateau de pêche à Wakayama - fishing boat in Wakayama
Port de pêche à Wakayama - fishing port in Wakayama
The mountainous areas where Binchotan is produced are densely forested. Because of the hilly terrain, a highly varied arboriculture has developed here, and these regions are known throughout Japan for their citrus fruits and plums.
Collines de Wakayama - hills in Wakayama
Route des montagnes à Wakayama - Mountain roads in Wakayama
Case du producteur de charbon - house of charcoal producer
These hills are also home to the Ubamegashi oak, a medium-sized tree with extremely hard, dense wood that sinks when immersed in water. It has been exploited for millennia by a handful of silviculturists who manage the forest and produce, from its wood, the most renowned charcoals in the whole of Asia.
Ubamegashi, le chêne de Wakayama - Ubamegashi, oak tree from Wakayama
THE PRODUCTION PROCESS
ubamegashi wood is cut into long, relatively thin logs, which are straightened by adding wedges. The wood is stored for some time to dry. At the end of the drying process, the logs are placed vertically in an earthen kiln and the fire is lit. Two phases then follow.
1. The carbonization phase:
The wood burns slowly at low temperatures (around 400°C) for several days. The wood is thus slowly transformed into charcoal.
Tas de bois de chêne pour la production de charbons binchotan - pile of oak wook for the production of binchotan charcoals
Four pour la production de charbons binchotan - Oven for production of binchotan charcoals
2. The activation phase :
After a few days of carbonization, the kiln door is opened, allowing air to rush in and fan the flames. The temperature in the kiln then rises considerably, reaching over 1200°C. This is the activation phase.
Producteur de charbons actif binchotan au travail - producer of binchotan charcoal at work
Charbons actifs binchotan sortant du four - Binchotan activated charcoals comming out of the Oven
Refroidissement des charbons - cooling down charcoals
Détails du charbons actif binchotan - details of binchotan activated charcoals
WHAT HAPPENS DURING ACTIVATION
The tars contained in the pores created during the carbonization phase will volatilize under the effect of the intense heat, forming a very large exchange surface, corresponding to around 1000m² per gram of coal! It is these substance-free pores that give coals their adsorption capacity.
Schémas explicatif de l'activation des charbons binchotan - explaination of the activation process
ADSORPTION, THE PHYSICAL PRINCIPLE BEHIND ACTIVATED CARBON PROPERTIESPrincipe de l'adsorption - Principle of adsorption
Adsorption (not to be confused with absorption) is the phenomenon whereby molecules suspended in a liquid attach themselves to the solid surface with which they come into contact.
It's a principle very commonly used in industry in certain devices using activated carbons to capture various compounds, and decolorize or clarify liquids such as beer, for example.