The different categories of tea are grouped based on the processing they undergo. The six most common classifications of tea are: white, yellow, green, oolong, and post-fermented.
Different classes of tea undergo the same process with only minor differences, depending on what type of tea is being made.
Plucking is the first stage in the tea process. Tea flushes include a terminal bud and two young leaves. These leaves are then picked from the tea plant bushes twice a year during early spring and early summer. Picking tea leaves in the fall and winter is uncommon.
Higher quality and more expensive tea is picked by hand. Depending on the skill and preference of the picker, hand-picking can be done several different ways. Generally, the picker pulls the flush by grabbing the tea flush with the thumb and forefinger. The picker then snaps back the forearm or even the entire upperbody.
Tea flushes can also be picked by machine. However, the machinery used to pick tea generally crushes and tears the leaves and flushes.
Shortly after the tea is picked, the leaves begin to wilt almost immediately. The process of enzymatic oxidation or browning, begins to take place. Browning, along with exposure to a cool breeze, serve two purposes. First, is to dry the leaves and remove the moisture. Second, the drying aids in breaking down protiens into amino acids which increases the caffeine content as well as changing the flavor of tea.
In the third step of the tea process the tea leaves are bruised in order to promote oxidation. The leaves are lightly bruised by shaking them in a bamboo tray or basket. Machinery can also be used to further disrupt or macerate the tea leaves. The oxidation also helps to release juices and enzymes which can change the flavor of the tea.
The fourth step in the tea process, for those that require it, is fermentation.For this process the leaves are placed in a climate-controlled area where they become darker. During this process the chlorophyll in the leaves is broken down, and tannins (plant hormones that change color and taste) are released. The tea producer chooses when the oxidation will be stopped. The stopping point is dependent on the desired qualities in the final tea as well as weather conditions. Oxidation is arguably the most important step in the tea-making process as it aids in the formation of many color, taste and aroma compounds.
The fifth step in the tea process is fixation. Fixation, also known as shāqīng, is done to stop oxidation at a certain level. This is accomplished by slightly heating the tea leaves. This deactivates their oxidative enzymes and removes unwanted scents without altering the flavor of the tea.
The sixth step in the tea process is unique to yellow teas. The tea leaves, after fixation, are allowed to be lightly heated in a closed container, which causes the previously green leaves to turn yellow in color. The resulting leaves produce a beverage that has a distinctive yellowish-green hue and distinct taste.
The tea leaves are then rolled into strips by hand or using a rolling machine. This rolling action also causes some of the sap, essential oils, and juices inside the leaves to ooze out, which enhances the taste of the tea.
Drying is done to "finish" the tea for sale. This can be done in a myriad of ways, however, baking is the most common.
The final step of aging is not required for every tea. This process consists of additional baking or fermentation.