Tea (Thea sinensis) is an evergreen plant from camellia family. Botanists usually distinguish three strictly related tea types – from China, Assam and Cambodia - all three are used for commercial production.

Camelia sinesis, Chinese bush, can reach a maximum height of 3-4,5 metres and it grows best in China, Tibet and Japan. It can survive very low temperatures and can produce five-centimetre leaves even for a hundred years.

Camellia assamica assamica is thought to be a tree rather than a bush and it can reach even 15-18 metres of height, producing leaves 15-30 centimetres long. It grows luxuriantly in tropical climate and it produces leaves usually for about forty years.

The third type, from Cambodia, Camellia assamica subspecies lasiocalyx is also a tree, which can grow to the height of about 4,5 metres and it is used mostly for creating hybrid species.

Tea plants grow and mature most luxuriantly in a hot and wet climate. The most favourable weather conditions are temperatures of 10-30°C, 2-2,5 metres of rain annually and the height of 350-2450 metres above sea level. The combination of height and humidity gives the desirable slow pace of growth. The higher tea grows, the more aroma and flavour and the better quality it has. A lot of best known teas from all over the world – noble sorts of Ceylon teas, Chinese Weyi, the best varieties of Indian Darejeeling – come from bushes cultivated at the height of 1200 metres.

Types of tea

We distinguish six basic types of tea – white, green, Oolong, black, aromatised and pressed – and also a lot of varieties in every category which gives us a total amount of nearly 3000 teas from all over the world, depending on the established method of processing:

Produced on a very limited scale in China (originally in Fujian province) and Sri Lanka. Young buds are picked before bloom, then subjected to the wilting process, during which they get rid of their natural moisture, and then they are dried. Curled buds have a silvery shade (and are sometimes called “Silver Tips”). They give a very bright straw-coloured infusion.

• GREEN TEA

Green teas are often described as “not fermented”. Freshly picked leaves are left to dry and then subjected to thermal processing in order to stop fermentation (or oxidation), which could spoil the leaf.

Oolong is usually referred to as “not totally fermented” of “half-fermented” tea and is produced by China and Taiwan (still called Formosa in tea terminology).

Methods used for its production as well as its varieties vary greatly depending on the region, but black tea processing consists always of four basic stages – wilting, curling, fermenting and burning (drying).

Green tea, Oolong and black tea are used in the production of aromatised tea. Additional aromas are mixed with leaves in the last stage of processing, before packing.

During the reign of the Tang dynasty Chinese producers started to manufacture tea in the form of hard bricks, by subjecting leaves to steam processing and then by pressing them into the shape of cubes or bricks before the final drying. The tea bricks maintain all the basic features of its kind.

Name of tea

Before the English language adopted the word tea, a leaf was called interchangeably tcha, cha, tay,and tee. The English word originates not from Chinese word cha in Standard Mandarin language but from the word “te” in Chinese dialect from Amoy. The word te was transformed into thee in Dutch, because it was mostly Dutchmen who brought the first tea to Europe and the new product became known under the name of thee in German, te in Italian, Spanish, Danish, Norwegian, Swedish, Hungarian, Malayan, tea in English, thé in French, tee in Finnish, teja in Latvian, ta in Korean, tey in Tamil, thay in Ceylonese and Thea for scientists.

Mandarin word cha was transformed into ch’a in Cantonese dialect and it was adopted as cha in Portuguese, as well as Persian, Japanese and Hindi. It changed into shai in Tibetan, chay in Turkish and czaj in Russian. The Polish name herbata which is an exception originates from two Latin words: herba thea – herb and tea.

Properties of tea and tea compounds

Research has shown that tea definitely is ahead of coffee when it comes to beneficial influence on human organism – it contains fewer harmful fats and less caffeine. Green tea should be drunk by the youth, over 10 because of its high fluorine content which prevents dental caries. For older people and those who suffer from hypertension a delicate brew from the second infusion is recommended.

Green teas contain more soluble compounds (40-50%) than black ones (30-40%). Good tea characterises not only with an excellent taste and aroma – a lot of beneficial compounds can be extracted from a high quality variety. Nowadays, there are some legends about beneficial effects of green tea consumption, the example of Japan clearly confirms those stories. After American nuclear attacks in 1945, it was foreseen that as a result of radiation sickness, three times as many people would die than it indeed happened. Scientists suspect that the reason for lower mortality is green tea which can absorb nearly a half of harmful strontium 90. The studies on lungs cancer incidence have shown that Japanese people go down with this disease less often. According to doctors green tea effectively prevents diseases such as lung, breast, colon, prostate, stomach cancer, and when used externally can prevent even skin cancer. Even one cup of green tea daily can have favourable influence on our health.

Tea is a plant of a very complex and various chemical composition. Its properties change during the technological process – the composition of dry tea is more diverse and complex than that of fresh leaves.

The most important soluble tea components are:

1. Alkaloids – the best known alkaloid present in tea and coffee is caffeine (up to 4,5%), but in tea it occurs under the name of theine. Tea contains more caffeine (theine) than coffee, however, while making a brew we use less tea than coffee and that is why a cup of tea is slightly more delicate than a cup of coffee. Additionally, theine by binding with tannin, acts less aggressively on cardiovascular and central nervous system.
Quick excretion of theine is its considerable advantage, as a result it cannot be deposited in human organism and even frequent tea consumption does not cause a risk of intoxication. It is thanks to alkaloids that the tea leaves infusion has a stimulating effect on the nervous system, reduces drowsiness and fatigue, it widens blood vessels in the internal organs and muscles, speeds up heart action and lungs ventilation. Theine has a beneficial effect on our mood and by increasing excretion of neurotransmitters it helps to concentrate. Thanks to theine tea flavour changes during processing – after brewing bitter fresh leaves gain pleasant tartness, which is the distinctive feature of the infusion. Green teas contain theine in non-oxidised form, while in black teas 40-50% of theine oxidize. What is interesting, strong Ceylon teas contain less theine than usually considered as gentle Chinese teas, but regardless of origin, high quality teas contain more theine than those of lower quality. Other alkaloids such as theobromine, theophylline, adenine and xanthine have diuretic properties and cause dilation of blood vessels.


2. Protein compounds – constitute 16-25% of dry tea. Those which are present in black teas blunt their taste. A lot of amino acids are generated during green leaves processing, which in higher temperature react with other tea compounds forming aldehydes responsible for the aroma of tea. Nearly 20 amino acids which can have a regeneratin effect on the human nervous system were found in tea.

3. Tannins – constitute 13-30% of dry tea leaves – these are catehins, polyphenols and their derivatives. Freshly brewed tea contains a lot of caffeine and few tannins that are extracted more slowly than caffeine. In the course of brewing more and more tannins move to the liquid. The infusion becomes tarter and its taste worsens. Drinking strong tea infusions can be harmful because the excess amount of tannins has a powerful effect on mucous membrane, limiting absorption of nutritious compounds, especially proteins. Tannins bind calcium, magnesium, iron, zinc, copper and other important micronutrients. Tannins destroy also the vitamin B1 contained in food. That is why, tea kept for many hours after brewing, for example in a Thermos flask, should not be drunk. It is better to keep boiling water in a Thermos flask and make a brew just before drinking.

4. Essential oils – constitute merely 0,08% of green tea leaves. Additionally, during processing 75% of those oils disappear while new ethereal compounds are created instead – in the final product nearly 30 of them were found, with aroma of rose, honey, vanilla, lemon, lilac or spices. Thanks to such a wide composition of aromas it is not hard to obtain a unique blend typical only of teas from certain parts of the world. Essential oils as very unstable compounds, disintegrate most often as a consequence of wrong storage or wrong tea brewing process. The biggest amount of oils is found in red teas, which are often used as additives to other tea types in order to enhance the quality of the brew.

5. Pigments – thanks to them a brew can take different colours: light green (chlorophyll), dark olive-green, yellow, pink, reddish brown or dark brown (xanthophyll, carotene). Most of pigments responsible for colour are very unstable and can be easily oxidized.

6. Inorganic compounds and microelements, mostly iron compounds and metals: magnesium, sodium, manganese and non-metals: silicon, potassium, calcium have a beneficial influence on electrostatic processes which take place in our organisms. Unfortunately, only trace amounts of fluorine, iodine, gold, copper, phosphorus and potassium penetrate into the tea infusion.

7. Vitamins bind and limit absorption of toxic heavy metals such us lead, cadmium or mercury as well as decrease the cholesterol level. In this way vitamins protect our organism against poisoning, prevent cancer and arteriosclerosis, reduce symptoms of allergies. The most important are bioflavonoids, usually known as vitamin P, which can remove harmful free radicals from the organism. Red and green teas have the strongest antiradical effect, better than black teas. Apart from vitamin P, also provitamin A, vitamin B1, pantothenic acid, vitamin PP, vitamin C and vitamin K can be found in tea infusions.

Strong tea infusion is a good antidote for stomach upset, because tea can cleanse digestive organs by absorbing substances which are harmful to human organism. That is why it is recommended to drink tea especially after fatty and heavy meals. Tea can increase the amount of vitamin C in the liver, kidneys, spleen and adrenal glands. Thanks to essential oils and their purifying properties tea can beneficially influence the lymphatic system.

Among red teas Pu-erh deserves special attention. Pu-erh is produced in province Yunnan, in China. Thanks to beneficial influence on metabolism it helps reduce weight, and by stimulating effect on the liver Pu-erh speeds up the metabolism of alcohol.

Tea, especially green tea, is not only a drink. Recently, cosmetics with green tea extract such as face creams, body lotions, hair shampoos and deodorants have become very popular. Vitamin B2 contained in tea can improve skin layers, while vitamins P and K additionally strengthen the walls of capillary veins. Thanks to the flavonoids, tea gained respect as a remedy which prevents skin ageing and as a wonderful UV filter. Tea infusion in combination with henna is used as a hair dye, which in addition strengthens hair roots, preventing hair loss. The strength of the infusion should be adjusted to hair colour – the darker, the stronger brew should be, which has to be rubbed into hair after the last rinsing.

Tea has wide applications in pharmaceutical industry. Natural caffeine (theine) is obtained from dust tea. Vitamins C and PP are extracted from thicker tea leaves, and then used in various infections treatments. Strong tea extracts are used as sleeping pills and painkillers, substituting even morphine.

Japanese people use tea seeds to obtain an oil called tsubaki by cold pressing. Apart from applying it for consumer purposes, it is used for producing cosmetics. Soap is produced from worse varieties. Oil is used for maintenance of delicate mechanic devices and for impreganting wooden tea packages in order to protect tea from strange smells.