Green Tea Processing: Picking, Oxidation, and Shaping

General Processing

I will have a whole section on processing, but we must understand two small details to advance further.

Two very general, sweeping ideas to start:

  1. All tea comes from the same tea plant, Camellia Sinesis.
  2. All tea starts off with similar processes.

Only the methods of production or processing change the type of tea. For example, white tea sits out and on the drying mats a little longer than the green tea, allowing it oxidize just a little bit longer. Thus producing white tea.

Harvesting for Green Tea

Farmers can harvest or pick tea in all four seasons, but some teas are better picked in certain seasons. In many areas green tea can be three times a year. In some cases they can be picked for a fourth time. The first harvest occurs in late April and early May. The second harvest is during June and July. While the third harvest occurs in late July and into August. Depending on that year’s climate and related factors, there may be a fourth pick.

Picking and Quality

IMG_6289Farmers pick the terminal bud and tippy leaves from the plant. Leaf quality is determined by the leaf composition. Typically, two leaves and a bud is considered good quality. But in general, leaf quality follows this order: Bud -> Bud + 1 leaf -> Bud + 2 leaf -> Bud + 3 leaf -> Bud + 4 leaf. Everything 4th leaf and below are considered tertiary leaves. (Tertiary leaves are usually considered lower quality. Ironically a lot of tertiary leaves are used in puer, which can often fetch a very high price tag.)

Flavor is dependent on many things, but there are a few indicators that we can find by looking at the tea leaves. The most obvious is the size of the leaf. There can be giant leaves and small tips. You can compare the size of the leaf to the size of the stem. The bigger the stem the more sugary characteristics. We can look at the leaves for bug bites. Bug bites are a good indicator of a good tea growing area. If the leaves seem more red than usual, then we know the tea sat a little longer on the wok than usual. On purpose? Maybe.

Oxidation

% Oxidation By type: Green (0-5), White (5-15), Oolong (20-90), Black (100), Puer (Post Fermentation)

Oxidation is where the difference in the type of tea takes place. You may have noticed that I skipped withering and sorting. That’s because I separate classes of tea based on their percentage of oxidation. All steps prior to this step occurs in the processing methods of most teas. Green tea is any tea that has oxidized from 0% to 5%, but is normally oxidized closer to 0% It has the least oxidation of all teas. It is important not to confuse green puer with green oolong. Puer goes through a fermentation phase and can have various oxidation levels from 30% to 90%. Puer is a class of its own.  

I also place caffeine content on this scale but in reverse, sort of. The most caffeine is found in teas that are lower in oxidation. This means that we can say green tea has more caffeine than black tea.

Shaqing – Kill Green

Shaqing is a heating process that stops oxidation and preserves the characteristics of tea. It gets rid of the grassy smell that tea has and also makes the leaves easier to roll. There are a few types of heating forms, we will touch on Barrel, Wok Kettle, and Wok Churning. Barrel is usually used on tea plantations, and usually produces a lower quality green tea. Wok Kettle is usually middle quality. Wok Churning is where the tea master’s skill really comes in, as this can be considered to produce the best quality of green tea. The tea sits in the bottom of a pan, usually with a wood fire underneath, and the tea master goes through a set hand motions that produce a higher quality tea. This is a critical step in the tea process and can really destroy good quality tea if done wrong.

Shaping

The shaqing step heats up the leaves and makes it possible for the tea master to shape the leaves. This step is usually done right after shaqing, when the leaves are still hot. For a lot of green teas this step is usually done by hand in the wok.

There are a few different style of shaping for green tea. The most relevant are rolled, strand, and crushed leaves. The rolled style produces a different flavor, mainly because it extracts slower since the leaf is rolled. These are often seen as lower quality. Stranded teas are usually a lot softer than the rolled leaves and of higher quality. Crushed leaves are crushed by machine.

After this shaping the leaves are left to dry further, packaged, and shipped to us.

As stated in the Green Tea Introduction, this section of green tea is just a high level of processing. The following posts will cover; Determining Quality Green Tea, Brewing Green Tea, and My Experience in Hangzhou.

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