Tea Manufacturing Process
Tea plants favour temperate, wet climates with rainfall of approx. 8 inches per year and daily sunshine of about 5 hrs. on an average. Long bright days should be followed by rainy nights amid the fresh winds and the loose, deep, acidic soil of high altitudes.
The First Flush Teas (March / April) are light, floral and aromatic. The Second Flush Teas (May / June) are smooth, full bodied and fruity. The Autumnal Teas (Nov / Dec) are slightly dark and have a deep complex aroma.
During quality periods i.e. First Flush or Second Flush, two leaves and a bud are picked - this is called fine plucking, resulting in high quality teas. At other times, even three or four leaves and a bud are plucked - this is called coarse plucking. The plucking cycle is maintained at about 7 day intervals. The plucked leaves are collected in bamboo baskets, taking care that they are not crushed by overloading the baskets.
The plucked leaves are delivered to the factory for weighment. Each plucker is paid against the quantity (weight) of green leaf that he/she brings in.
The green leaf, after eradication of any foreign matter, is spread on "withering troughs", loosely, to a depth of 6 inches. Fans are installed to pass air over the green leaf while it withers. The object of the withering process is to get rid of the moisture content in the green leaf and prepare the leaf to withstand the strain of rolling without breaking up. Period of withering can vary from 18 to 24 hrs. depending on the moisture content. The leaf, when properly withered, gives off a fragrant odour.
The withered leaves are rolled under mild-pressure between metal plates which results in twisting of the leaves. Due to the pressure, the cells in the leaves rupture, thereby releasing the juices in the leaves, rendering te rolled leaves to moisten.
The rolled leaves are spread on fermenting beds and left to ferment for a period of 3 to 4 hrs. The leaves are loosely spread to a thickness of 1 or 1.5. inches. Good fermentation results in the colour of the leaf to change to reddish brown giving off the characteristic aroma after the juices in the rolled leaves react with each other and the air. The Fermentation process is conducted at 80-90% humidity and the temperature is maintained at 70-80° Fahrenheit. A slight rise in temperature gives the tea a burnt taste whereas a slight fall in temperature stops the fermentation. During fermentation the leaves first heat up due to the chemical reactions and subsequently begin to cool down. A correct assessment of the timing, when the leaves start cooling, is needed to determine when to halt the process of fermentation.
The fermented leaves are then fired (i.e. heated) in a drier machine. The object of this process is to arrest fermentation and slowly dessicate the leaf in such a way so as to extract the moisture without scorching the tea and at the same time, preserving its quality and other characteristics to the optimum level. The leaves are passed through the drier and remain within the drier for a period of approx. 20 mins, at a temperature of around 240 to 250° F. This results in the leaves moisture content to come down to 20 - 25% from 60 - 70% before it enters the drier. A second firing is also given shortly thereafter.
Sorting of different grades is done by sorting machines which are fitted with wire mesh trays that revolve or vibrate. The tea is passed over wire mesh of varying sizes so that the whole leaf, broken leaf, fannings and dust grades fall at different places. These sorted teas comprise the different grades.
The different grades of tea are then packed into plywood chests / paper sacks lined with aluminium foil inside. Each lot is generally packed in a minimum of 5 chests / sacks or more. The chests / sacks are sealed and the grade name, garden name, lot number (called an invoice), chest number, gross and nett weight, year of manufacture etc. are printed on the chests / sacks with stencils. Lastly, Darjeeling CTM user licence number and Darjeeling "CTM-applied for" are also stencilled onto the tea chests / sacks.