Talk:Tea processing
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Chart change proposal
tea chart
icetea (talk) 00:10, 17 June 2010 (UTC)
I am proposing to revise the primary processing chart:
icetea (talk) 20:29, 17 June 2010 (UTC)
It what way is this chart is better than the one already there? Sjschen (talk) 21:38, 17 June 2010 (UTC)
hi; i think the original chart is good but it might be with the terminology, my knowledge of tea processing mostly comes from china/taiwan terminology, i am not an expert on japanese or indian tea processing but i think most of the processes are similar or overlap. From what i see the main diffence is in the charts is the division of steps.
- bruising: this step i include in the withering/fermentation with buising i call
laying 作青(includes setting and tossing)
setting 靜置 letting the fresh leaves rest
tossing 攪拌浪青also called shaking (but this is not rolling)
- curing: according to the chart this looks like it includes different processes, one is post-fermentation and the other is firing or what i call roasting. (i am going by the chart not the article)
this is what i would propose or something like this,(but like wiki's way we need to reach an agreement).
green tea綠茶: fixation殺青 > rolling揉捻 > drying乾燥
yellow tea黃茶: fixation殺青 > rolling揉捻 > sweltering悶黃 > drying乾燥
green Puer青普: sun fixation曬青 > rolling揉捻 > sun drying曬乾 > (usually aged)
dark tea黑茶and dark Puer熟普: sun fixation曬青 > rolling揉捻 > piling 渥堆 > sun drying曬乾
white tea白茶: withering (fermentation) 萎凋 > fixation殺青 > rolling揉捻 > drying乾燥
oolong tea烏龍茶: withering萎凋 > fermentation發酵 > fixation殺青 > rolling揉捻 > drying乾燥
black tea紅茶: withering萎凋 > rolling揉捻 > fermentation發酵 > drying乾燥
Explanation of some tea making processes:
oxidation氧化 (enzymic): a natural chemical change in the tea leaf that begins after harvesting and accelerates if leaf cells are broken and exposed to oxygen.
withering萎凋: water loss by respiration and evaporation and leaf becomes more pliable, dryness and heat aid in this process.
fermentation發酵: actually enzymic oxidation, noticeable change chemical composition and leaf becomes darker, moisture and heat aid in this process.
fixation殺青: to rapidly stop the fermentation through water loss caused by heat.
rolling揉捻: breaking the leaf cell walls exposing sap to leaf substrate and air, and shaping.
drying乾燥: making the leaves ready for storage.
Two different methods of making black tea (in India, Sri Lanka for example):
There are two methods used to rupture the leaf cells prior to fermentation.
orthodox method: the traditional way of making black tea, a batch of leaves go through the roller and are macerated and twisted.
CTC(crush-tear-cut) method: leaves are continuously fed through the machine and are rolled and go through a sharp teeth.
icetea (talk) 23:31, 17 June 2010 (UTC)
I agree with some of the changes in terminology. Namely the change with wilting and kill-green to withering and fixation, respectively. Here are my comments on the processes, which given in the parenthesis in italics:
- "fermentation發酵: actually enzymic oxidation, noticeable change chemical composition and leaf becomes darker, moisture and heat aid in this process." (The word fermentation is implies biologically driven breakdown something. However, the leaves are as you stated changed through enzymatic oxidation and as such should be listed in that manner. For this reason I prefer the term "oxidation")
- "fixation殺青: to rapidly stop the fermentation through water loss caused by heat.": (As stated I do like the use of "fixation" more than "kill-green". However, the "fermentation" is not stopped by water loss through heat but is due to the denaturing of the oxidation enzymes through heat. Proof of this is how fixation/sha-qing can be done by steaming which is a decidedly wet method.)
As for bruising and curing, although the processes included in these two groups are different, they are basically the more or less the same mode of operation in terms of the goal. this was essentially how the chart was constructed, by looking at the goal of the process rather than the actual details entailed in the process. For instance, bruising in black and oolong tea making are accomplished differently with:
- CTC Black: heavy crushing and cutting with serrated rollers
- Orthodox Black: lighter crushing with rollers
- Oolong: light damaging of the leaves around the edges to various degrees
Although all the processes are rather different, the intended result is to damage the leaf structure/cells to release the enzymes and expose the insides of the leaves to oxygen, thus contributing the production of flavour molecules. Since the goal they should be included them under the same group, namely "bruising", which is a fitting term.
The same argument goes to the curing of tea, of which one is biotic and auto-oxidation (post-fermentation) while the other is heat-based denaturing (roasting/firing). The processes are different but the intended result is to cure the teas into 熟茶, and produce something that is less astringent, less "harmful" to the gut, and more pleasant to drink (smoothness). Since the intended goal is the same, the processes are listing under the same group.
As for to splitting brusing into 3 steps (作青,靜置,浪青), to me "laying 作青(includes setting and tossing)" and "setting 靜置 letting the fresh leaves rest" are more or less withering processes, with the goal being to expel excess moisture from the leaves prior to further processing. As such, it does not contribute enough to oxidation to be listed under oxidation. "Tossing" (浪青) is neither withering nor oxidation since the process does not significantly reduce moisture nor does it contributes to oxidation (that happens after 浪青). In fact 浪青 is really there to damage the leaves to help oxidation and thus a unique step on its own, which is bruising.
For a Chinese version of the chart please look here. Perhaps you can give some comments on it too.
The description of the processing of different teas is not completely accurate when stated. My comments are given in the parenthesis in italics in the following:
- "green Puer青普: sun fixation曬青 > rolling揉捻 > sun drying曬乾 > (usually aged)"(Green pu-erh is type of green tea, the aging is a curing process with auto-oxidation and biotic fermentation)
- "dark tea黑茶and dark Puer熟普: sun fixation曬青 > rolling揉捻 > piling 渥堆 > sun drying曬乾" ("dark tea" is the result of post-fermenting a finished green tea through a composting process. 渥堆 only proceeds after the a green tea is more-or less finished (not as dried))
- "white tea白茶: withering (fermentation) 萎凋 > fixation殺青 > rolling揉捻 > drying乾燥" (withering contributes very lightly to oxidation)
- "oolong tea烏龍茶: withering萎凋 > fermentation發酵 > fixation殺青 > rolling揉捻 > drying乾燥"" (oolong leaves are damaged after withering, and a key step of the process along with the partial oxidation)