You know what tea is, because everybody drinks tea, one way or another. All over the world, in many different languages, 'tea' basically has only two names - in some places it is called by the name "tea", or variations of that, and in other places its name is some variation of "cha".
But not every liquid with the label "tea" is necessarily tea. And not all tea is Chinese tea, although China still produces the most tea, ahead of India, Kenya, Sri Lanka, and Turkey.
The original, and only real, tea plant has the botanical name Camellia sinensis, and it is an evergreen shrub which is native to parts of Asia. The drink is made by pouring hot, or boiling, water over the leaves which have been first treated or cured in a number of ways.
There are "herbal teas" made in a similar way - pouring hot water over the fruit, leaves or flowers of particular plants such as rosehip, chamomile, or rooibos (red bush) - and these are more correctly, called "herbal infusions", or "tisanes". There are also some genuine teas, from the Camellia sinensis plant, which have additional herbal flavors added to them.
The Camellia sinensis plant is a small tree which produces green leaves all year round, and has smallish flowers with white petals and a bunch of yellow stamens. Although native to south and east Asia, nowadays it is cultivated across the world in tropical and subtropical regions. Some plants are also cultivated as far north as Cornwall and Scotland in the British Isles, and as far south as Waikato in New Zealand. The plants require a rainfall of at least 127cm (50") of rain per year. It can also be cultivated at high altitudes, up to 1,500m (4,900') where it grows more slowly but acquires more flavor.
There are two principal varieties of the Camellia sinensis plant. The original Chinese tea is known as Camellia sinensis var. sinensis. and is used for most Chinese teas, as well as Formosan, and Japanese tea. Also popular is Camellia sinensis var. assamica, named after the Assam area in India, which is used in Pu'erh, the Chinese fermented tea from Yunnan, as well as most Indian teas. Other strains and varieties have been developed within these, with leaf size being the chief criterion for classification. The Assam type teas have the largest leaves and the China type teas the smallest leaves.
The plant can grow into a 3 meter (10') tall tree, and sometimes even taller, but is usually kept trimmed to a comfortable height to make picking the fresh new leaves easier, as it is the young leaves that are most desirable. The plants can be propagated from seeds, or from cuttings, and it takes 3 years before harvesting can begin, and 4 - 12 years before it produces seeds. The growing tips are harvested, with the bud and the first two or three leaves being snapped off. The next flush of growth can be picked off the same bush after another week or two.
There are six basic types of tea, with clearly visible differences in both the product before steeping and the appearance of the beverage. The first type is the original and probably the best-known in the western world, black tea. Then there is green tea, yellow tea, white tea, oolong tea, and the dark fermented teas such as Pu-erh tea.
The way the tea is processed decides which type of tea is produced, and involves some variation of these main processes.
When tea was originally discovered some 3,000 years ago, it was used for medicinal purposes, but eventually it became a recreational and social drink for people in all walks of life, all over the world. There are a number of distinct varieties, different ways it can be processed before use, a whole range of activities and ceremonies associated with its consumption, and an assortment of beliefs about its spiritual and health benefits.
Firstly, there is caffeine, that wonderful pick-me-up. A 250ml (8oz) cup of tea, depending on the type, the brand, and how it has been brewed, usually contains between 30mg and 90mg of caffeine. There is significantly less caffeine in green tea (35 - 70 mg) than in black tea (60 - 90 mg). Tea also contains small amounts of a couple of other stimulants, which are similar to caffeine.
Most tea has a slightly astringent taste when you drink it. This means that the membranes in your mouth contract resulting in an immediate dry, chalky sensation - which some people find pleasant, and others less so. This taste is caused by the natural antioxidants, known as polyphenols, which are the most abundant compounds in the tea leaves and are beneficial to health. Only some teas have the astringent flavor, others have a sweet, floral, or just plain grassy taste.
Some cultures like to drink their tea hot and strong, others sip on a fairly weak brew. In many cultures milk and/or sweeteners such as sugar or honey are added to a heavier concoction, while lemon is added in some places, Yak fat in others. Each person has his own favorite cup of tea, to the extent that there is a common saying in English to politely express distaste for something - "That is just not my cup of tea."
Then there are a variety of health benefits associated with the different types of tea. Tea contains powerful antioxidants which can protect against cancer, and improve metabolism for weight loss, and even reduce the chance of developing Alzheimer's disease.
In fact most people who drink tea, do so because it makes them feel good, and - most importantly - because it is a part of relevant social interaction.