Processing of Tea

Wide varieties, green, black, oolong, and white teas are created by different processing methods. The flavor of tea depends upon how the tea was processed, in what part of the world the plant grew, time and quality of harvest, weather, soil conditions, altitude etc. It is an established fact that quality comes from the field, and the factory’s job is to preserve it. Yield and Quality are usually in inverse relationship with each other. Generalization of all plants irrespective of its individual traits dilutes the optimum potential from fruition.

Withering of Tea leaves is an activity wherein the freshly plucked leaves are dried with the ambient or warm air (air with a hygrometric difference of minimum 4* Fahrenheit). The purpose of withering is two fold. First is to remove about 20 to 40 % moisture so as to make it flaccid and render it capable of withstanding further rigors of processing. This is known as physical wither. Second is to increase the concentration of enzymes in the leaf, while simultaneously allowing the chlorophyll to undergo chemical decomposition. This is known as chemical withering. Withering is done only for making Black Tea and not done for making Green Tea. Finer leaf can take harder wither; coarser leaves can not take hard withers. An average factory may have up to 40 withering troughs having Axial Flow fans of 7.5 HP each.

Steaming or Pan Frying is a process wherein the freshly harvested leaves are subjected to steaming or frying on low heat to deactivate all the enzymes present in the leaves. Steaming or drying is done only for making of Green or Oolong tea, and not done for making Black Tea.

Rolling or CTC is a process by which the cells of the leaves are ruptured. Rolling is a gradual process of cell rupturing, wherein the leaves are rolled in rolling tables for certain duration, at the end of which the leaves become twisted and curly. This process is known as the “Orthodox” process. CTC is a rapid process of complete cell rupturing, wherein the leaves are fed into the CTC rollers through a BLC or Rotor-vane for Cutting, Tearing and Curling, at the end of which the Tea leaves become round and granular in shape. A factory may have 12 rolling tables of 15 HP each or 6 CTC machine of 30 HP each and another 25 HP for a BLC machine.

Fermenting is a process wherein the leaf is oxidized for a duration of 1-3 hours during which the exposed juices of the leaves react with atmospheric oxygen. This is where the polyphenols and liquoring characteristics of all Black Tea is developed. There is no fermentation of Green Tea. This is the most potent stage for bacterial growth in tea, hence immaculate hygiene is essential at this stage.

Drying is a crucial process from the end users point of view. It serves a dual purpose. One, that of arresting further Oxidation of leaves by rapidly reducing the moisture content of Tea from 60%-70% to 3%-4%. Second, drying locks in the carefully developed characteristic flavors and provides keeping quality or shelf life to the Leaves. Driers may be Coal, Furnace Oil or Gas fired. A factory may have 4 to 5 dryers using 50 HP each.

Sorting of Tea is the process by which different sizes of grains / leaves of tea are separated. In the process of sorting, flakes, fibers and stalk of tea is also removed to give it a clean appearance. There is nothing wrong with drinking clean teas of mixed sizes. The terminologies used in naming of grades have a Chinese origin, and confusing at its best.

Packing of Tea is the final process on a plantation, wherein the graded Tea Leaves are packed in approved bulk packages. The packaging choices available are Wooden chests with an Aluminum or poly Lining, Jute Bags with poly liner, HDPE Bags with poly liner, Multi walled Paper Sacks and Vacuum Packs. Wooden chests have become almost obsolete. Paper sacks can be palletized, and hence preferred by exporters. Jute Bags are preferred by domestic buyers due to its resale value.