Tea Plant- Characteristic, Cultivation, Processing etc.
- Botanical name: Camellia sinesis (syn. Theasinensis)
- Family: Theaceae
- Vernacular Names: Chai (Hindi, Bengali, Marathi), Thyalli (Tamil) Theyakn (Telugu)
Origin and Distribution
Tea is more popular among non-alcoholic beverages and more than half of the world’s population is addicted to tea. India or China or perhaps both of there countries are native home of tea. The ancient records show that tea we grown in China as early as 2700 B.C. but it has never been found to grow there in a truly wild state. In 1823, occurrence of wild tea plants, Thea assanica in the mountainous regions of Assam and the adjoining areas was reported and it was suggested that cultivated varieties of tea are derived from this plant. It is assumed that Chinese travellers carried tea seeds from Assam to China, However, experimental cultivation of tea began in India between 1818 and 1834 from seeds reimported from China, although it was growing in her own forests all along. It has been considered by some that China and Assam teas had separate origins; the large-leaved Indian varieties probably originated from wild plants near the source of the Irrawaddy river in Assam or northern Burma, whereas the narrow-leaved Chinese varieties perhaps had a separate origin in China itself. Teh tracks introduced tea from China to the West in the later part of the 16th century. It was brought to Japan in early 18th century it was introduced into North America by the English emigrants. Today England teady, other countries in its imports and is the greatest tea drinking nation in the West.
For many years China held its monopoly is cultivation of tea on commercial scale and was the only exporter of tea. It is now widely cultivated in Ceylon; India, Indonesia, East Africa Brazil Peru and Argentina. Today, Ceylon and India are the two largest producers of tea, sharing over 10,000 tea gardens. In India, the principal tea-growing states are located in the Brahmaputra and Surma valleys of Assam, and Darjeeling and Jalpaiguri districts of north Bengal. These accounting for over 70% of India’s total production. The remaining 30% of Indian tea comes from mountain slopes of the Nilgiri and Annamalais, Kerala, Karnataka, Rachi, Karga and Kumnon regions.
Catilif setersis is an evergreen perennial shrub of ahrail tree, attaining height of 9-15 metre is Brutial condition, but under commercial cultivation it is never allowed to grown beyond 0.7-1.5 m I has simple, elliptic to lanceolate, coriaceous and secreted leaves. The young leaves are beset with mirarous oil glands which impart characteristic fragrance and aroma. The white or pinkish forget flowers are borne in leaf axils, either singly or in groups of two to four. The fruit is a trilocular capsule with one brown seed in each locule.
Cultivation of Tea
The sub-tropical and tropical mountainous regions are suitable for tea cultivation, For cultivation of tea an annual rainfall of 100-150 cm and temperature of 24-30°C is needed. Excessive dry periods are not suitable for plant growth. It requires some shade for faster growth. The bushes thrive best in deep, well-drained friable loam or forest land rich in organic matter.
Tea plant are raised from seed. Some bushed allowed to grow in tea gardens and seeds are collected from these bushes. Seeds are first sown in nurseries and they germinate in about a month. Seedlings are ready for transplantation in about a year. After transplantation, plants are allowed to grow for four years. When they attain a height of about 2 m, they are pruned to a height of 45-50 cm. The main aim of pruning is to promote branching. The tea bushes are then regularly pruned to maintain their proper shape. After pruning, new shoots appear during the rainy season. A certain initial growth, known as plucking level, is then established, above which the new leaves are harvested. Waterlogging is harmful to tea plants. To provide shade to tea bushes leguminous trees like Albizia procera, A. Chinensis, Dalbergia Assamica, Derris Robusta, Gliricidia sepium and Erythrina spp. Are planted in tea gardens. In addition to shade, these trees supply some of the essential plant nutrients and their roots ventilate the soil.
Growth, of tea bushes is not uniform throughout the year. A period of rapid growth alternates with a dounant period. The periodic appearance of new leaves is called a flush. Leaves are plucked with the beginning of active growing please. In northern India, leaves are plucked 3-4 times in a year but in winter season (dormant period) plucking continues throughout the year, and it is done at weekly or fortnightly intervals. The first picking is usually made when plants are about 5 years old. Leaves are usually picked up by women by hand or by seissors. During picking young tender shoots with the terminal bud and two to five leaves immediately below it are removed. The young plucked shoots are transferred to basket suspended from the waist or back of the plucker. A skilled worker can pluck up to 50 kg of tea leaves every day.
The quality of tea depends upon the age of leaves. The terminal buds are the most valued in the trade and commonly referred to as golden tips. The smallest leaf forms orange-pekoe the second leaf pekoe, the third
leaf pekoe-souchong, the fourth leaf souchong and the fifth leaf congou grades of tea.
Processing of Tea
There are four commercial categories of tea:
- Black or fermented tea,
- Green or unfermented tea
- Oolong or semi fermented tea
- Brick tea.
Black tea is commercially the most important, and it is produced mostly in India, Ceylon Indonesia and East Africa.
Processing of tea is usually done in the following four steps:-
The fresh tea leaves contain about 75% water. The plucked leaves are spread over withering racks, stacked one over the other for 12-18 hours. In this process, leaves lose their moisture. Sometimes heated air is forced over the racks if atmosphere is humid. The leaves slowly and evenly become soft and flaccid and ready for rolling.
Rolling imparts characteristic twist to the leaf, breaks the leaf cells and exposes the juices to the air for fermentation to set in. The rolling is done by special types of machines. Thereafter, leaves are completely dried and the final product is known as green or unfermented tea with dull green leaves. Black or fermented tea is prepared by fermenting green tea..
The process of fermentation is carried out in specially designed fermentation chambers where temperature, humidity and air circulation can be regulated. Since leaves are damaged during rolling, the enzyme polyphenol oxidase becomes active and acts on the substrate polyphenol. The oxidation results in the production of orthoquinones which provides characteristic dark colour to the leaves. To achieve fermentation, rolled leaves are spread in thin layers on a glass or aluminium surface. The process of fermentation is completed within three hours. The less fermented tea is more pungent and longer fermented tea is soft and deeper in colour. During fermentation, the colour turns bright red and leaves develop a characteristic aroma and flavour.
After fermentation, when leaves change their colour, they are subjected to drying. The main aim of drying is to stop the process of fermentation and to reduce the amount of moisture present. The drying is done in specially constructed ovens. The fermented leaves are exposed to a current of hot air at 90°-100°C for 20-25 minutes. Careful regulation of temperature is essential as excessive heat will scorch the leaves while lack of it will result in improper drying. When dried with care the product is brisk and pungent with a typical black appearance.
Oolong tea is partially fermented product, intermediate between green and black tea, having the flavour of the former and the colour of the latter. Brick tea is prepared from the waste left after the preparation of black and green teas.
 Grading and sorting
Tea obtained after consists of intact leaves and their small and larger pieces. Hence its grading and sorting is necessary from commercial point of view. It is graded on mechanically oscillated sieves where leaves of different sizes are separated. The following are some major recognised grades of tea trade :
- Broken orange pekoe (B. O.P.)
- Flowery broken orange pekoe (F.B.O.P.)
- Broken pekoe (B.P.)
- Orange pekoe (O.P.)
- Flowery pekoe (F.P.)
- Broken orange pekoe fannings (B.O.P.F.)
- Fannings and dust.
Various brands of tea available in the market are made by blending different tea grades. They are then packed and sent to the market.
Qualities of Tea
The quality of tea depends primarily upon the variety of the bush and the agroclimatic conditions. The distinctive character of tea is mainly due to three principal constituents, essential oils, alkaloidal fraction and polyphenols. The aroma and flavour of tea is due to the presence of an ethereal oil, theol; the stimulatory and refreshing properties due to caffeine alkaloid; and the bitterness and astriugency due to polyphenols (tannins). Chemically, tea consists 2.5% theine, 13-18% polyphenols and essential oils. In addition, it contains several of the B-complex vitamins and nicotinic acid. It is astringent stimulant, diuretic and nervine.
Important Improved Varieties of Tea
Two improved varieties of tea cultivated in India are Darjeeling tea and Assam tea. Darjeeling tea is more fragrant and soft than Assam tea. In India three research stations: (1) Tocklai Experimental Station, Assam, (2) Tea Research Institute, Dooarg West Bengal, and (3) Government Tea Experiment Farm, Palampur are engaged in Improving varieties of tea and their processing.
TV 23, Phoobsering 312, TV 9, and Tukdah 253 are some improved strains of tea cultivated in India.
Tea in India
India is world’s largest producer, consumer and exporter of black tea. In India tea production was one million ton in 2011-12. India is the only country which produces both CTC and orthodox tea in substantial quantities. India produced approximately 650 million kg CTC tea, most of which was consumed at home.
India’s 98% of tea production comes from Assam, West Bengal, Kerala and Tamil Nadu. It has more than doubled its production since 1947, mainly by increasing yield through the use of improved methods of planting and optimal use of inputs.
Tea is mainly a labour-intensive industry providing employment to over a million people directly and another million indirectly by way of ancillary occupations. Tea is a major foreign exchange earner for India. In 1951, Indian tea export was only Rs. 800 million, in 1991-92 it increased to Rs. 12,000 million and in 2007-08 it was over 16,950 million.
Tea Board, set up under the Tea Act 1953, promotes development of the tea industry. The board comprises of a chairman and 30 other members representing owners of tea estates, persons of tea estates, manufacturers and dealers of tea, consumers, members of Parliament and governments of principal tea growing states.
Tea Trading Corporation of India (TTCI) was established in 1971 to create a stable export market for Indian tea, particularly in its value added form, such as packaged tea, tea bags and instant tea. Other activities of the Corporation include marketing of tea for domestic consumption, management of tea gardens, warehousing of tea and establishment of other facilities beneficial to the tea industry, Institute of Tea Technology provides practical and theoretical training to tea growers.
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