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March 2012

  /    /  March

George Orwell, in his famous classic, Animal farm, wrote, ‘all animals are equal, but some are more equal than others’.

This memorable Orwell’s statement holds true for tea. There are different types of tea and among them some confer superior healthy and medicinal benefits than others.

The term healthy teas, in this case, mean tea that offers extra benefits to human health beyond the basic nutrients, quenching of thirst and stimulation.

There are basically three types of tea depending on the processing technique. These are: unfermented, partially fermented and fully fermented tea. The term fermentation is actually used erroneously, it should be oxidised teas.

Types of tea

Tea plant, scientifically known as Camellia sinensis is evergreen tree which grows in high altitude regions. In Kenya, it does very well around Mt. Kenya, Kericho and other highlands.

The young leaves are harvested either by hand, shears or by machines and delivered to factories for processing.

Depending on the level of oxidation of tea leaves during processing, the following teas are obtained; White tea, Green tea, Oolong tea, Black tea, Pu’erh tea and Roobios tea (red tea). Tea beverage is obtained when any of these teas is added to boiling water.

White tea, as the name suggests is white in colour and is the healthiest of all types of teas.

To process white tea, the buds and young tea leaves are picked when they are very undeveloped, shortly before they are fully open. Sometimes the young buds are sheltered/covered from sunlight to prevent development of the green pigment called chlorophyll that is found in plants.

The plucked young leaves are immediately steamed and dried; these two processes are sometimes done in the farm. Quick and minimum processing helps the white tea to retain the highest levels of antioxidants and has the lowest level of caffeine than any other tea.

The closest cousin of white tea in powerful health constituents is green tea. Chinese were the first to make green tea. Chinese used to expose the plucked and chopped tea leaves to vapour from hot water shortly after harvesting followed by drying in the sun. At the outset, it was thought that this was just a drying process. It is now known that the process did more than drying; it inactivated an enzyme in tea called polyphenol oxidase. Inactivation of polyphenol oxidase ensured this enzyme did not interfere with the good compounds in the tea leaves. The final colour of this type of tea remains green after processing; leading to the name, green tea.

Nowadays, green tea is processed by steaming (scientifically known as blanching) the plucked tea leaves and drying them immediately after cutting and rolling. This inactivates the enzymes leaving all the healthy and medicinal chemicals in green tea unaffected or slightly affected.

Green tea is well known for its super health benefits, but it is poorly received by many consumers due to its flavour. But the trend is changing.

Oolong tea is a partially oxidised tea. Processing of Oolong tea follows similar steps as green tea, but the cut and rolled tea leaves stand for slightly longer periods (usually less than an hour) before drying. The waiting period prior to drying allows the enzymes to partially breakdown some chemical in tea leaves lowering its healthy qualities. This greenish-black tea falls in-between green tea and the well known black tea.

If the tea leaves are withered, macerated and allowed to stand for longer periods of time usually between 90 and 120 minutes before drying, the enzymes break down the chemicals producing the black tea. This is the most common and widely consumed tea.

Pu’erh is a type of tea which comes from the large leaves of a tea plant. Its processing is similar to that of black tea. The uniqueness of this tea is that, once picked it is piled and aged for as long as 50–100 years.

Roobios tea comes from a shrub in South Africa. It is naturally caffeine free – making it a good choice for those do not prefer caffeine.

Origin of tea

The origin of tea as a beverage is traced back to China during the reign of emperor, Shen Nung in about three thousand years Before Christ (BC). Tea was accidentally discovered when wind blew leaves into a kettle of boiling water.

‘‘Tea can provide vigour to the body, contentment of mind, and determination of purpose’’ those were the complimentary words from the Chinese Emperor after drinking tea. In other words, he was referring to stimulation of body and mind.

From China, the practice of tea drinking spread to Japan and India from where it was exported to England. The English popularized and commercialized tea. From England, tea spread to her colonies and America.

Tea is the most popular and widely consumed beverage in the world, second to water and well ahead of beer, wine and carbonated soft drinks.

Among the types of tea, green and oolong tea are commonly consumed in Asian countries mainly China, Japan, India and Thailand, while black tea is most popular in European countries, their colonies and America.

Black tea accounts for 80% of tea consumed in the world while green tea accounts for approximately 18%, Oolong tea and the other types of tea account for the remaining 2%.

Black tea versus green tea

Generally, drinking of tea is associated with several health and medicinal benefits derived from chemicals called catechins which have antioxidant properties.