There are three basic varieties of tea… green, black and oolong. All are made from the leaves of the Camellia sinensis plant and the only difference between them is the processes used to make them.
Green tea is made by steaming the leaves quickly. To make black tea, the leaves are exposed to the air or fermented, which darkens the leaves and gives them flavour, while for oolong the tea leaves are only partially fermented.
The flavours of teas vary depending on where the plants are grown. Different growing conditions, horticulture methods, production processing, and harvesting times also affect flavours. Teas from different areas can be combined to make teas with a particular flavour, called blended teas. English Breakfast Tea, for example, is a blend of Chinese, Ceylonese and Indian teas.
Herbal teas (such as chamomile and mint) are not really teas at all, as they are not made from the Camellia sinensis plant. Drinking herbal teas is not considered as healthful as drinking green, black or oolong teas.
Green tea and health
Green tea has long been associated with a long and healthy life in many Eastern cultures. Nowadays, extracts from the tea are used in beverages, health foods, and dietary supplements. But does it actually contribute to health?
Free radicals are molecules that are damaged. These damaged molecules can, in turn, damage cells which may become cancerous. Antioxidants may reduce or prevent some of this damage. Catechins are a type of antioxidant found in tea leaves. They are part of a family of molecules called flavonoids which have anti-oxidative and anti-carcinogenic functions.
It’s the flavonoids that give green tea its reputation as a healthful drink. The average quantity of flavonoids in a cup of this tea is higher than the quantity found in the same volume of other healthy drinks, such as fresh fruit juices, wine or 花茶茶葉 vegetable juices. However, the quantity of flavonoids can vary widely between different teas and tea products.
Tea making and drinking
You get more antioxidants from freshly brewed tea, compared with other forms of the drink such as instant tea and decaffeinated tea. However, to maximise the anti-oxidants in green tea, you need to steep the tea for at least three minutes; five minutes is ideal.
Most people in most countries drink their tea hot. America, of course, is the exception… about 85% of the tea drunk in the US is iced tea. The problem is that iced tea often contains relatively small amounts of catechins compared with hot tea. This is due to the way iced tea is made.
Iced tea is usually made by boiling water to which tea is added. Once the tea has been stewed for about five minutes, the liquid is cooled by adding water to double its volume, after which it is refrigerated.
Adding water dilutes the concentration of catechins. To make sure that your iced tea contains the same amounts of antioxidants as your hot tea, allow for the dilution by adding 50% more tea than usual to the boiling water.