Sawdust Briquette Charcoal (SBC) comes in 2 shapes: hexagon and square bar, with a hole in the center. Generally, square shape is in great demand in Japan while every other countries accept hexagon shape.
SBC is produced from compressed sawdust with no chemical or additives added. It is completely safe for BBQ and shisha using. Restaurants and consumers popularly use SBC because of its high burning temperature and quite long burning time (about 3 hours over 650 Celcius degree).
In Vietnam, most of SBC factories burn charcoal by rectangular kilns in 13-20 days. After that, they cool down charcoal naturally within the kiln. This kind of kiln improves the quality and quantity of grade-A charcoal.
To make black charcoal, they carbonize the wood (partial burning with little air) at temperatures between 400 and 700 °C. Subsequently, the technician seals the kiln until the burning stops and the heat slowly dies away. Therefore, the surface of charcoal turns black.
Black charcoal is soft and retains the outer layer of the wood. As a result, it is also easy to ignite and burns hot enough that it was used as fuel for tea ceremony, and ordinary daily food cooking.
Almost all charcoals around the world are soft black charcoal.
They made White charcoal by carbonizing the wood at a moderately low temperature. But near the end of the process, the kiln temperature is raised to approximately 1000 °C to make the wood red hot.
When making White charcoal, you need to be quite skilled in removing the charcoals. Because the charcoals turn deep red from the kiln. Then, you have to quickly smother it with a covering of powder to cool it. In addition, the powder is a mixture of sand, earth, and ash. So the color of the charcoal surface turns white, which is origin of the name "White charcoal".
Temperature rises quickly, then quick cooling, burns up the outer layer of the wood leaving a smooth hardened surface. That is the origin of the name “hard charcoal”.
White charcoal may take some more time to ignite, but its thermal conductivity is way better than ordinary black charcoal. The heat from burning white charcoal lasts long enough to be used as a fuel.
In the scientific world, they use White charcoals for industrial purposes like electronic components to medical applications .
They make compress charcoal from charcoal powder, usually sawdust briquette charcoal and white charcoal powder. The powder is mix with a small quantity of safe adhesives such as starch, then the mixture is compressed with heat into a cylinder shape with hollow core.
Compress charcoal is very easy to start burning. However, its burning time is short and temperature is not so high. So people often use it as burning starter for other kinds of charcoal, and used for picnic BBQ.
Bamboo charcoal is essentially black charcoal.
In Vietnam, there are many bamboo trees, especially in the Northern provinces so it is abundant material source for
bamboo charcoal production.
Due to the purpose of using, bamboo charcoal will be crashed into small pieces (about 2-5cm) or keep long and straight (15cm). Crashed bamboo charcoal is usually packed in non-woven bag at 1.5 or 3 kgs net weight, to be put under the wooden floor. The long straight pieces are uncovered, then being put in wardrobe, cabinets, car, refrigerator. Thanks to its porous and lightweight characteristics, bamboo charcoal is widely used for humidity control, especially in Japan house construction.