Last month, I published a series of short stories highlighting my experiences in Gisakura and Gatare tea factories found in Nyamasheke District. While visiting the two estates, I learned how to pluck tea. In addition, I got acquainted with the step-by-step process of transforming green leaves into the beverage we consume regularly.
Tea processing is done in five major stages namely rolling, withering, oxidation, drying and sorting. Today, let’s have a look at the source of the steam that aids a number of functions.
The first stage in tea processing is withering. This is the removal of moisture content from green leaves. Upon delivery, leaves usually register a moisture content of more than 70%.
Fresh leaves are spread out on ventilated troughs where excess moisture is sucked out of the leaves. The exposure to air reduces humidity to the range of 65 - 70%. Classification of tea depends on the degree of oxidation. This procedure determines the color, flavor, taste and aroma of the final product. As oxidation is effected, green leaves turn brown.
At the drying stage, steam is released from a powerful radiator. The leaves are then exposed to temperature levels of up to 130°C. Heating is regulated to ensure required levels of drying are maintained. This procedure further reduces humidity to as low as 3%.
Gisakura and Gatare tea factories use wood boilers to generate heat. According to Stephen Wahome, the factory manager of the former, wood is economical and produces better results. His factory grows eucalyptus trees in order to ensure a constant replenishing of firewood. "Eucalyptus trees grow faster. In addition, they have a high calorific value." He told me.
Production of firewood is a long, slow process. It takes at least eight years to grow trees. After harvesting, wood is dried for about six months before use. The drying process reduces moisture content to 15% or so.
Firewood management is a carefully implemented task. Stacking of firewood is done in a tower system supported by what tea processors call cigarette sticks. Stacking is done while creating space between logs to allow aeration.
Researchers are currently carrying out experiments on more environmentally friendly boilers. Are the days of wood boilers numbers? Time will tell. In the meantime, they are serving us just fine.
The author is visiting all 30 districts of Rwanda. His tour of Nyamasheke is sponsored by Nyamasheke District, The Click Creations, Tec-Global Ltd, Elimo Real Estate Ltd and Exposure. Follow him on Twitter @GeoExposure