by V. Jegatheesan
Charcoal is a controversial fuel these days due to climate change and atmospheric pollution fears. Nevertheless, this fuel was a standard feature in the kitchens of most Malaysian houses. It is still being used although on a much reduced scale. Making charcoal is not a matter of just heating wood until it is burnt. It is more involved than that requiring the right type of wood and the right method. However, it is still a very basic process with no high tech blast furnaces or machinery. A recent visit to the Khay Hor Holdings Sd. Bhd. Charcoal Factory provided me with good insight on how charcoal is made.
The factory is located in Kuala Sepetang, formerly and better known as Port Weld. Kuala Sepetang is within the Matang mangrove forest reserve, which at 40,000 hectares is the largest and best-managed mangrove forest in Malaysia. The west coast of the peninsula has many other mangrove forests, Kuala Selangor for example, but they do not replant the chopped trees thus depleting the forest. Matang, however, is recognised as a good model of sustainable mangrove forestry and conservation.
The images above are from https://www.rainforestjournal.com/kuala-sepetang
There are a few factories in the area, but the one we visited was the only factory that gave a tour. This was led by Mr. K. Y. Chuah, a member of the owning family, who, in his work clothes of a sports shirt, shorts and sandals, gave us a spirited and engaging tour of the factory and its operations.
Among the mangrove, the two species most commonly used are Rhizophora apiculata and Rhizophora mucronata. Mangrove trees are locally referred to as bakau. Any wood can be made into charcoal. However, these species can withstand high heat. The charcoal-making process involves high heat to remove the water content in the wood. This is smoked out rather than burnt out. It also gives a shine to the charcoal.
The wood from these trees is initially very heavy, as we found out when carrying one of the logs, because of high water content. In fact, this wood will sink in water and not float like other woods, because there is no air space due to water saturation. It is after all a mangrove swamp tree.
The kiln is igloo shaped and there are six of them located in a large shed. The bricks used are of the same type as used in housing. The structure is plastered with very fine clay and sand to seal the kiln completely. It does take an expert to do this perfectly. The kilns are all 7m in height by 6.7m in width. These sizes are specified by the Forestry Department to make it easy to calculate the duty to be paid.
Wood is stacked to fill up the kiln. It will weigh some 50 tons inside. This is high because of the water content of the wood and when the process is completed, it will weigh some 10 tons only. The fire is not inside as the wood is not burnt. The fire is on the outside and it is the heat that slowly goes in to heat the wood and remove the water content. There are six flues or vents around the kiln to allow the vapour to escape. Simply put, heat goes inside and heats the wood to release the water content.
This is just the first stage with the fire burning for 14 days. Workers in three shifts have to check every 3 to 4 hours to top up the wood and keep the fire consistently going. If not topped up and the fire lowers, the oxygen leaks inside and the fire follows inside and burns the wood.
The vapour comes out of the vents. It is in fact steam, which is very hot and has a strong pungent odour. Expertly smelling and seeing the colour, as well as using a thermometer to be sure, the workers will know when it is ready to reduce the fire to a smaller one. Through experience, the workers know how to control the slow fire. It is still hot inside but the vapour is reduced and, thus, not as hot as before. This will continue for another 11 days after which there is no longer any vapour. The workers then shut down the fire and seal the kiln completely. It will take another 7 days to cool it down completely.
Finally, the kiln opening will be hacked, the bricks removed and the charcoal taken out. The six kilns in this factory are used in turn to continuously produce charcoal.
The condensed vapour is referred to as vinegar; it is liquid oil, which is collected. Mr. Chuah extolled the virtues of this and of other products, which can be used as mosquito repellents and soaps with no chemicals added.
The factory is in a swamp area and the stench takes some getting used to. The canal by the side is used to bring in the wood from the forest. It is a tidal canal and therefore used on certain days only. Contract workers are paid to cut and transport the wood and are paid after delivery. As the forest is harvested, the cutters have to go in deeper and so it takes longer to bring the wood in.
The Forestry Department annually allots the specific lots for harvesting and they have to use their allotment. Otherwise, the following year’s allotment will be reduced or the licence cancelled. The replanting is also managed by the Forestry Department but tendered to contractors.
Mr. Chuah explained that Japan buys 70% of the production and they insist on these species. According to him, the Japanese despite being very high tech still believe in charcoal. They use it as barbeque fuel as more people prefer traditional methods. For those who can afford it, houses are built with a layer of charcoal beneath to keeps the houses warm in winter and it absorbs odour. In addition, among its many other uses, charcoal is also used as an absorbent.
All in all, it was a very interesting tour and appreciation of charcoal. Questions were in our minds as to whether charcoal is environmentally friendly to use. It is not fossil fuel and it is touted as being green. However, how much of the carbon released is recaptured by reforestation?