Camellia Sinensis = the species of plant whose leaves and buds are used to produce “tea”; a genus of flowering plants in the family Theaceae.
As discussed in Tea vs Tisane (Herbal), in order to technically be called “tea”, it needs to come from the camellia sinensis plant. Because it comes from the same plant type, the nutritional value will be very similar. The amount of certain components will be greater or less depending mainly on the method of processing. As well, the appearance of the leaves, color of liquor and taste profile (and price) will differ depending on where and how the leaves are grown and how they are picked, processed and stored.
The tea leaf is green year-round and has jagged edges all around, resembling the teeth of a saw. During the fall, the plant produces a flower that has a yellow stamen and white petals. Around 5 days after the flower blooms, it withers and in its place, a seed grows.
Tea trees can be largely categorized into 2 major types – small leaf type and large leaf type:
The small leaf type, or China’s sinensis forma bohea, can be commonly found in countries like China,Japan andKorea, located in the Temperate [Variable] Zone. The small leaf type is ideal for making green tea. This is because the polyphenol content is low, resulting in low activity of oxidation and a more profound taste.
Of the large leaf type, the assamic found in and near India, and the Chinese large leaf type (sinensis forma macrophylla – found in the district of Yunnan,China) are two most representative. The large leaf type has a high content of polyphenol, resulting in high activity of oxidation and making this type ideal for making black tea.
There are thousands of known variations produced and enjoyed all around the world and there may be more that are unknown – I hope so :). Before going into the major categories that most teas will fall under, let’s define a word that will be used very often throughout – oxidation or oxidize : “to convert (an element) into an oxide; combine with oxygen” (as defined by www.dictionary.com). Basically, when a substance (in this case, the tea leaf) comes into contact with oxygen, the oxygen changes the properties of the substance. This is what is happenening when, for instance, a sliced apple starts turning brown in color; or when a boat in water starts rusting. (DIFFERENT from “fermentation”, which we will go into more detail in another post.)
There are ways to stop oxidation by “getting rid” of the component (a.k.a. oxidase enzyme on the dermal layer of the tea leaf) that causes it – some refer to this as “kill green”. In tea, this process is done through applying heat to the leaves. This can be done in a variety of ways – natural sunlight, steaming, pan-firing, roasting, etc.
Okay. Enough technical lingo. Back to the main point – categories of tea:
- White Tea (no oxidation, no processing)
A specific variation of camellia sinensis is used exclusively to produce white tea. This variation only grows in specific environments, currently found mostly in China (there is news of white tea being grown in Mount Baekdu of North Korea). The name is derived from the physical appearance of the leaves – fine silver/white hairs along the leaves, giving the leaf almost a “fuzzy” look. The harvested leaves are left out in natural sunlight to wither/wilt. Other than this process to stop oxidation, no further processing (steaming or pan-firing) is done to the leaves.
One of the most widely known and drunk variation of the camellia sinensis, every region, company, person might have their own “method of madness”. Depending on the exact process used, the appearance, color, taste, fragrance and texture will be different.
NOT ALL TEA IS EQUAL.
Most farms and tea estates will produce “different grades” of green tea. This is usually determined mainly by the time that the leaves are picked. Usually, the buds and leaves will grow back repeatedly for multiple pluckings in one season. The leaves picked earlier (early spring) will be smaller and more delicate in flavor (and pricey!). The leaves picked later in the year will be larger in size and will usually have a stronger taste profile. The amount of certain components (nutritional value) will vary slightly depending on the time picked. For example, leaves picked later in the year are exposed longer to the sunlight and, as a result, will contain a higher level of tannins and lower levels of caffeine. More on the science later…
To make green tea, oxidation in harvested leaves is stopped by either steaming or pan-firing or the combination of the two, and then processed (cool, roll, loosen, dry). Varying the “heating” time and repeating certain steps (cool, roll, loosen, dry) will change the flavor profile as well as appearance of the leaves and liquor.
Pan-firing will result in a more roasted, smoky, full flavor while steaming will result in a more light, vegetal, crisp flavor. Again, appearance and taste profiles will differ depending on origin of leaves and exact processing method.
- Partially Oxidized Tea (oolong, hwang cha, etc.)
This is the category that probably contains largest number of varieties of teas.
Partially oxidized tea is tea that has been allowed to oxidize a certain amount before stopping oxidation. Depending on the amount of oxidation and the exact process used, the taste, fragrance and color will all be different.
The oxidation is somewhere between green tea (no oxidation) and black tea (full oxidation). If discussed in percentage, the oxidation amount is usually between 15-90%. Oolong and Hwang Cha are two examples of partially oxidized teas. Both follow very specific steps in processing.
Hwang Cha is a tea traditionally made in Korea since the days of Kings. Today, depending on the company or tea maker, the oxidation will be anywhere between 50-80%.
The term “oolong” is actually indicative of a specific type of tea, processed a specific way. The term had been linked with teas that were similar in taste (partially/semi-oxidized) and even those teas that weren’t processed in that specific manner got stuck with the title “oolong”. There are many, many, many (perhaps hundreds) variations of oolongs, all tasting different depending on the degree of oxidation. Those oxidized for a shorter amount of time will taste closer to a green tea and those oxidized for a longer time will taste closer to a black tea. Oolongs are usually not oxidized less than 15% because there would be almost no difference from green teas. Although green teas are not oxidized on purpose, the leaves can and will become slightly oxidized usually during the heating process before the oxidase enzymes are “killed off” (aka “kill green”).
Similar steps used to process green tea is used to make partially oxidized tea. But instead of killing off the oxidase enzymes (a.k.a. “kill green”), the leaves are allowed to oxidize. The entire process typically takes 2-3 days.
In Chinese, semi-oxidized teas as a collective are called 青茶 (chung cha; literal translation: “blue-green tea” or “celadon tea”).
In Korean, oxidized teas as a collective are called 발효차 (bahl-hyo-cha; literal transalation: “oxidized tea”). Add the term 부분 (boo-boon; literal translation: partial) in front to create the term “partially oxidized tea” (부분 발효차boo-boon bahl-hyo-cha).
- Black Tea (full oxidation)
Black tea is when the tea leaves are completely oxidized. The term “black tea” comes from the English. In Asian countries, this tea is known as 홍차, or hong cha (red tea – not the same as rooibos, which is actually not “tea” because it is not made of tea leaves).
After the tea leaves are picked, they are withered and dried to reduce moisture levels. There are two ways to process black tea – orthodox or CTC (crush, tear, curl or cut, twist, curl). These methods will be discussed in a separate post.
The “Orange Pekoe” system is used to determine the grade of orthodox processed black tea, and another grading system is used for CTC teas (which is used primarily for tea used to make teabags). The grading is done according to the size of the leaves – whole leaf, broken, fannings and dust. These grades can be broken down even further.
- Pu’erh Tea (post fermentation)
Pu’er(普洱 – 보이 boi in Korean) is the name of a city in Yunnan Province, China. Originating from this region, the pu’erh is a fermented tea. Just like the definition of “fermented”, good bacteria is allowed to form through controlling the level of moisture and temperature of the tea leaves. The live bacteria change the chemistry of the tea leaves, creating a unique taste and aroma.
Depending on the region of China, processing method and condition of the tea leaves, pu-erh tea is categorized as compressed pu-erh, loose pu-erh, post-fermented dark or black tea (흑차 heuk cha 黑茶 – not to be confused with the English black tea, which is known as hong cha – see above).
In Korea, pu’erh is usually categorized in the following way:
생차 saeng-cha – made of raw tea leaves that are crushed and compressed together to form a tight lump (variety of shapes).
숙차 sook-cha – slightly processed before being made into pu’erh, the tea leaves are fermented as loose or compressed form.
– 산차 sahn-cha – loose form of sook-cha
– 전차 juhn-cha – compressed form of sook-cha. Also known as “brick tea” or “coin tea” (made in the shape of old coins – round with a hole in the center)
- Yellow Tea (no oxidation)
Depending on who you talk to, the yellow tea can be similar to either a white tea or a green tea.
Some say that yellow tea is similar to a white tea in that both are not oxidized. The white tea is wilted while yellow is unwilted, but allowed to yellow.
Those that say yellow tea is similar to a green tea say that the process of making the tea is similar. But instead of drying, the moist tea leaves are stacked and allowed to yellow.
It is hard to say which method is “correct”.