PRODUCTION, IN THE KISHU REGION, WAKAYAMA PREFECTURE

The Kishu charcoals, also called "Kishu Binchotan" or "Wakayama Binchotan", are activated coals produced in Wakayama Prefecture, in the southern part of Japan. The term "activated" refers to a specific production process. To make charcoal, one needs to burn wood, of course, but obtaining activated coals is a much more complex operation. It is detailed here 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 best binchotan are produced is in the Kii Peninsula, south of Kyoto. This mountainous area is covered by a dense forest, and is called "the land of trees". A varied arboriculture developed there, and the area is known throughout Japan for its citrus fruits (mikan) and plums (ume).


collines de Wakayama - hills in Wakayama route des montagnes à Wakayama - Mountain roads in Wakayama case du producteur de charbon - house of charcoal producer



On these hills grows an oak tree called "Ubamegashi", a medium-sized tree, extremely hard and dense; it sinks when put into water. Ubamegashi has been exploited for thousands of years by a few foresters who manage the production of the most recognized coals throughout Asia.

Ubamegashi, le chêne de Wakayama - Ubamegashi, oak tree from Wakayama 



THE PRODUCTION PROCESS

Ubamegashi wood is cut into long and thin logs that are made straight by adding shims. The wood is stored for a few weeks to dry. After drying, the logs are inserted vertically into a clay oven lit by fire. Two phases will then succeed.

1. Carbonisation phase : Wood will burn slowly, at a low temperature (about 400°C) for several days. The wood slowly transforms into coals and millions of microscopic pores will apear on its surface. At this time, pores are filled with tar.

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 Four pour la production de charbons binchotan - Oven for production of binchotan charcoals four pour la production de charbon binchotan - Oven for the production of binchotan charcoals

2. Activation phase : After few days of carbonisation, the door is suddenly opened, air rushes in it, and triggers intense combustion. The temperature increases significantly to up to 1200°C. Tars who were imprisoned in the pores volatilize as a result of the intense heat.

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 THE ACTIVATION

Tars contained in the pores created during the carbonization stage will volatilize under the effect of intense heat and will thus form a very large exchange surface corresponding to about 1000m² per gram of carbon! This is what gives to the Kishu coals their adsorption capacities, free pores from any substance.

schémas explicatif de l'activation des charbons binchotan - explaination of the activation process

ADSORPTION, AT THE ORIGINE ACTIVATED COALS PROPERTIES

Adsorption (not to be confused with absorption) is the phenomenon in which molecules present in suspension in a liquid (or a gas) bind to the solid surface with which they come into contact.

Principe de l'adsorption - Principle of adsorption

According to this principle, particles responsible for unpleasant tastes and odors of tap water stick to the surface of coal.

This principle is commonly used in the industry; certain devices using activated carbon to capture chlorine, pesticides and herbicides, benzene, radon, solvents and other chemicals. Activated coals are very often found in powder for clarifying liquids such as beer.