In global terms, tea is the most popular beverage. Approximately 3.5 million tons of tea are produced each year. These figures refer only to tea from the tea bushes Camellia sinensis and Camellia assamica. Per capita consumption in Germany is 25 liters. The love of tea varies greatly from region to region. The East Frisians have the highest consumption in Germany. They drink around 10 times as much tea as the rest of the country. But they also occupy a top position worldwide, ranking third after the Irish and Libyans.
By the way: According to food law, the simple designation “tea” on packages may only be used for black tea or green tea. The other plants or parts of plants that make a drink with hot water are listed under the category “tea-like products”.
What’s in tea?
Among the most important ingredients of tea is caffeine. The content in tea leaves ranges from 0.9 to 5 percent, depending on the type of tea. So, with a cup of tea (150ml) you take 20 to 56 mg of caffeine. Compared to other caffeinated beverages, the effect of caffeine in tea is slower and lasts longer, because the released caffeine is bound to tannins.
The caffeine content of green and black tea is about the same. Some green tea varieties even contain more caffeine than black tea. However, the amount of caffeine that passes into freshly brewed tea depends largely on the water temperature at which the tea leaves are brewed. Since green tea is not brewed with boiling water like black tea, the caffeine content of green tea in the infusion is usually lower.
Tannins (polyphenols) are present in tea leaves in amounts of about 10 to 20 percent. They are said to have numerous health-promoting effects. The most important representative is EGCG (epigallocatechin gallate). Black tea as well as green and white tea are good suppliers of the healthy polyphenols. Tea also contains important minerals and vitamins. In addition to fluorides, which are important as caries protection, tea provides iron, zinc, vitamins A, E, C and numerous B vitamins, among others.
Black, green or white?
Germans still prefer black tea. It accounts for a share of 77 percent. However, green tea is becoming increasingly popular, currently still accounting for 23 percent of total consumption. We are not talking about two different tea plants here. Green and black tea are produced from the same leaf material. Only the further processing after harvesting is done in different ways.
- Black tea
Black tea, after withering and rolling, is subjected to a process called fermentation. During this process, the polyphenols (catechins and catechin derivatives) contained in the tea leaves are converted into theaflavins and thearubigens by the leaf’s own enzymes, known as phenoloxidases. The tea thereby changes its color and develops its characteristic aroma through the combination of the cell sap with oxygen.
- Green tea
Green tea differs from black tea only in that it is not fermented. After withering, the plucked leaves are steamed. Treatment with dry heat or steam inactivates phenoloxidases, which means that the catechins contained in the tea are not oxidized and the green chlorophyll is preserved. Accordingly, the content of polyphenols (tannins) in green tea is higher than in black tea.
- White tea
White tea is characterized by the special selection of tea leaves. Only the unopened leaf buds of the tea bush, which is grown in the Fujian province, located in southern China, are used. The mild flavor of this type of tea comes from the gentle light and air drying process. As a rule, white tea is a slightly anfermented tea, with the fermentation process occurring naturally during withering.
