Tea is a beverage produced by steeping top leaves and buds of the tea plant in freshly boiled water. Teas are classified by the manufacturing process, resulting in the three categories of fermented, unfermented and semi fermented. Unfermented tea is usually produced from the china plant and is grown mostly in Japan, China and to some extent Malaysia and Indonesia. The infused leaf is green and the liquor is mild, pale green or lemon-yellow and slightly bitter. Fermented tea is best made from Assam or hybrid plants. The infused leaf is bright red or copper coloured, and the liquor is bright red and slightly astringent but not bitter, bearing the characteristic aroma of tea. Semi fermented tea are produced mostly in southern China and Taiwan from a special variety of the China plant. The liquor is pale or yellow in colour and has a unique malty or smoky, flavour. The best known constituent of tea is caffeine, which gives the beverage its stimulating character but contributes only a little to colour, flavour and aroma. About four percent of the solids in fresh leaf is caffeine and one tea cup of the beverage contains sixty to ninety milligram of caffeine. The most important chemicals in tea are the tannins or polyphenols. Certain volatile oils contribute to the aroma of tea and also contributing to beverage quality are various sugars and amino acid.TEA PRODUCTION OUTFITOutfit used in tea production include tea leaf, tats, trolley, tunnel, enzyme, juice, rolling machines, tables, automated conveyor and dryers.TEA PRODUCTION PROCESSWithering Plucking the leaf initiatesthe withering page, in which the leaf becomes flaccid and loses water until, from a fresh moisture content of seventy to eighty percent by weight, it arrives at withered content of fifty-five to seventy percent.Fresh leave is spread by hand in thin layers onto trays. It is then allowed to wither for eighteen to twenty hours, depending upon several factors that include the temperature, and humidity of the air and the size and moisture content of the leaf Rolling At this stage, the withered leaf is distorted acquiring the distinctive twist of the finished tea leaf, and leaf cells are burst, resulting in the mixing of enzymes with polyphenols. The bunches of leaves are rolled between the hands, or by hand on a table, until the leaf is twisted, evenly coated with juice, and finally broken into pieces.FermentationFermentation commences when leaf cells are broken during rolling and continues when the rolled leaf is spread on tables under controlled conditions of temperature, humidity, and aeration. The most important is the oxidation by polyphenol oxidase of some polyphenols into compounds that combine with other polyphenols to form orange-red compounds called theaflavins. The theaflavins react with more units to form the thearubigins, which are responsible for the transformation of the leaf to a dark brown or coppery colour. The thearubigins also react with amino acids and sugars to form flavour compound that may be partly lost if fermentation is prolonged. Optimum fermentation is reached after two to four hours.DryingFermented leaf is dried on large pans or screens over fire. Heat inactivates the polyphenol enzymes and dries the leaf to a moisture content of about three percent. It also caramelises sugars, thereby adding flavours to the finished product, and imparts the colour associated with tea.
