The discovery and use of tea originated in China around 4700 years ago during the age of Shen Nong. In the legendary medicinal historical record of plants, Shen Nong Ben Cao Jing, it is written that “Shen Nong tasted a hundred plants and met with 72 different types of poisons daily, but all was cured with tea”. In the beginning, our ancestors simply chewed on the leaves of the Camellia Sinesis, which today is commonly called a tea plant, tea shrub, or tea tree. They then discovered that boiling the leaves created delicious soups and beverages. In modern China, there are a number of mountainous communities in Yunnan that have kept the custom of using tea as a culinary ingredient. For example, the Jingpo (Chingpo) and De’ang ethnic minority groups are still known for their salt-pickled tea.
The processing of tea leaves began in the period of the Three Kingdoms (220 AD – 280 AD). Tea leaves were harvested and laid out in the sun to dry before steeping. Several hundred years later during the Tang dynasty (618 AD – 907 AD), tea was steam-pressed into round cakes that were sent to the palace as tributes. These cakes of tea had to be ground up and brewed in a special tea kettle. Lu Yu , in his scroll Cha Jing, kept a detailed record of the making and drinking of tea during this period, popularizing tea-drinking across China. Tea drinking and tea culture reached its apex after the rise of the the Song dynasty (960 AD – 1279 AD. A popular tea ceremony developed whereby water was added to tea powder and mixed with a bamboo whisk, which spread to Japan and became what we now know as matcha. In the Ming dynasty (1368 AD – 1644 AD), Emperor Zhu Yuan Zhang favored loose tea over tea cakes and this preference for brewing loose rolled tea leaves has preserved to this day. The explosive popularization of loose leaf tea resulted in the worldwide development of modern tea all from the original green leaf of Camellia Sinesis.
THE SIX COLORS OF TEA
There are now hundreds of well-known teas around the world, causing a lot of confusion. In reality, there are only six different varieties of tea – green tea, yellow tea, dark tea, white tea, oolong tea and black tea. Although they all originate from the same plant, they differ in terms of how they are processed. For example, the tea plants in Long Jing village can be used to create any of the aforementioned six types of teas. Since the leaves from the plants in this region are more suited to making green tea, Long Jing village maximizes its natural advantages for a single type of tea.
Green tea, yellow tea, and dark tea are exposed to high heat immediately after harvesting, thus preventing the oxidization process of the leaves from taking place. It is also this process that allows the tea leaves to keep their original green color as it is the enzymes that cause the leaves to change color. This process is similar to how vegetables remain green during cooking when blanched. Prior to the Ming dynasty, tea was mostly pressed into tea cakes and the hot steam in this process created the same effect. In fact, the most common type of tea in Japan is still steamed green tea. After the Ming Dynasty and the rise of loose leaf tea, pan-fried tea leaves became increasingly popular and remain so today.
Green tea goes through the processes of heating, rolling (or shaping), and drying. After heating, green tea is rolled into different shapes, either flattened or molded into sheets, rolls, spirals, needles, or an orchid-shaped design. It then goes through a final drying process, either baking or pan-frying. Baked teas tend to be brighter in color and its aroma is more delicate or floral and its taste is lighter. An example of baked tea is Jing Shan from Xu Hang. Pan-fried teas have a richer aroma and taste, such as Long Jing tea from West Lake. The reason for green color of the leaves and brew of this variety of tea is mostly due to its initial heating process.
Dark tea undergoes the following process: heating, rolling/shaping, sun drying, fermentation, and pressing into cakes. After tea leaves are heated and shaped in regions such as Yunnan, Sichuan, Guangxi, and Hunan, the last step is simply drying the leaves in the sun and they are thus called sun-dried semi-refined tea. Long ago in order to supply tea to Tibet and Nepal, tea merchants from Yunnan and Sichuan had to travel long distances over mountains and rivers. During the arduous journey, the tea leaves were naturally oxidized, which was the original fermentation process for dark tea. Modern techniques use sun-dried teas as the base and combine the addition of micro-bacteria with humid conditions to generate man-made fermentation – and this is the unique feature of the black tea process. It is through this fermentation process that the bitter-tasting substances in the tea become weaker while also causing an increase in water-soluble pectin and sugars. This gives the tea its soft flavor and characteristic bittersweet taste.
White tea, oolong tea, and black tea are not initially heated. Instead, the enzymes in the plant are left to naturally oxidize the leaves. All three types of tea must first go through a withering process; after tea leaves lose their water content, they naturally begin to wilt and wither.
White tea’s process is simply withering then drying. The drying is carried out under weak sunlight or indoors and occurs after a relatively long wilting process. The process is the simplest, without rolling or frying, thus preserving the chemical composition of the tea leaves. In Europe, white tea is known as the most natural and healthiest type of tea. A variety known as Big White has a large quantity of fuzz and is most suited to making white. The dried tea is covered in white tea fuzz, giving white tea its name. When only one bud is collected and processed, the tea is known as Silver Needle Pekoe. If two leaves are wrapped around a single bud, the tea is known as White Peony. Due to the lack of rolling and frying in its processing technique, white tea has a very light taste and releases its flavor very slowly, making the tenth steep is just as mild as the first.
Black tea uses the shoots of suitable tea leaves as its base ingredient and undergoes wilting, shaping (cutting), fermenting and drying. It is a well-known fact that sliced apples turn brown. This is due to the damage wrought on its tissues when cut, which leads to an oxidizing reaction between the phenol and enzymes in the apple. This is similar to the process by which black tea is oxidized. In the process of shaping or cutting, the tea leaves’ plant tissues are damaged and the high quantities of phenol in the leaves are oxidized due to the activity of its enzymes. This gives rise to theaflavin, thearubigins, theabrownin, and other pigments found in black tea. These pigments, together with the amino acids, protein, sugar, caffeine, organic acids in the tea, gives black tea its color, aroma, and taste. When the fresh leaves are shaped, its tissues are damaged and the phenol in the tissue fluid seeps onto the surface of the leaf where it is oxidized, thus turning the leaf brown. The smooth dark color of black tea stems from this oxidization process as well as the precipitation of protein, pectin, and sugar as well as other organic substances during shaping. In Chinese, the name of this variety of tea, literally translated, is “red tea”. When it was first exported to Europe, it was called “black tea” due to its physical dark color. It is only after steeping that the redness of the leaves and brew manifest itself. Chinese black tea is typically shaped into long bars and is known as Kungfu Red Tea. Red tea outside of China is usually broken up into small stubs after shaping and is thus known as Black Tea Fannings.
Oolong tea lies in between green tea and black tea. The first half of its process is similar to black tea while the latter half resembles green tea. Its fresh leaves are first left to wither in direct sunlight (Shai Qing), then left to dry in the shade (Liang Qing), before being shaken gently in a bamboo basket to bruise the edges of the leaves. This shaking and drying process is repeated a number of types (Zuo Qing). Finally the leaves are pan-fried, shaped and baked. The shaking and drying technique is a special feature of the oolong tea process. Unlike the rapid oxidization of black tea through shaping and cutting, the Zuo Qing technique results in a slow oxidization of the leaf through the friction between the basket and the leaves. As only the edges of the leaves are bruised, oolong tea is green in color with red borders. The Zuo Qing process also causes the aroma of the tea to change – the light aroma of the leaves start changing into floral, fruity, and honey fragrances. After the shaking and drying, the oxidization process is stopped through heating before being shaped. With the differing intensity of the Zuo Qing process, the oxidization level of the tea leaves varies. There are four main regions which manufacture oolong tea: North Fujian Oolong (e.g. Da Hongpao), South Fujian Oolong (e.g. Tie Guanyin), Guangdong Oolong (e.g. Fenghuang Dancong), and Taiwan Oolong (e.g. Dongding Oolong). Oolong tea from North Fujian and Guangdong usually undergo a more intense Zuo Qing process and the oxidization levels are correspondingly higher. Thus, the brew is more orange in color and its taste richer while oolong tea from South Fujian and Taiwan is more yellow and mellow.
DEGREE OF OXIDATION & NATURE
A single tea leaf has the capacity to make a variety of different teas. The difference between the six main types of teas stems from differing oxidization levels. Green tea is not oxidized and the phenol in the tea is entirely preserved. For white tea and yellow tea, 5-20% of phenol is oxidized, while the range for oolong is 20-80% (the lightest oxidization being Tie Guanyin and Wen Shan Bao, and highest being Fenghuang Dancong and Eastern Beauty). The oxidization levels of black tea and dark tea stand at over 80%. The tables below summarizes the nature of the six types of tea and it is evident that this has much to do with the tea’s oxidization levels; the higher the oxidization level, the warmer the nature of the tea. This is why green tea is said to be cooling while black tea is said to warm the spleen and stomach. Looking at the color of the brew, we can see that the higher the oxidization level, the darker the color of the brew and the warmer the nature of the tea.
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