what "color" does Oolong classified as?

[wyardley]

From wyardley's link above.

I wonder about the sheng maocha sold to consumers? Old sheng maocha has clearly aged not lost it's flavour and aroma as green teas generally do and the young sheng maocha tastes much more like a sheng pu-erh cake than green tea.

I don't actually necessarily agree with the suggestion Robert made about the fermentation beginning when the tea is compressed.

[next paragraph quoted from a new reply I posted to that thread]
I'm not sure that the pressing is what changes the tea -- the tea is dried completely after it is compressed, and I think it's pretty well established that while maocha and compressed pu'er ferment slightly differently, both will ferment, and both can have similar end results (i.e., both will become dark and fermented with time). Your other observation (about the sealed bag) is a little more to the point - without air and moisture, the tea won't ferment. And of course, maybe green tea would end up fermenting as well, given sufficient air and moisture.

Keep in mind that Pu'er is a different major sub-varietal of the tea plant from the one used for most other tea plants, and that the production methods may also be slightly different from [other] green teas. Also, the way it's typically prepared differs slightly from the way you make most green tea. Plus, green teas have tons of taste differences from each other, which come from both differences in the varietal, time of harvest, exact method of production, etc. I don't think too many people have tried storing green tea in a warm, humid and oxygenated environment for 10-30 years, but I wouldn't be surprised if at least some sort of fermentation didn't take place if you did. Generally, green tea is prized for its freshness, and once it's sat around for 2-3 years, it may taste kind of stale / boring (pu'er tea can also go through some "awkward phases").

I prefer to just say "post-fermented" tea, and leave the question of whether young sheng is hei cha or not alone. From the limited research I've done, I believe the subject of at what point (if any) sheng becomes "dark" or "black" is a subject on which there isn't widespread consensus.

[entropyembrace]

Thanks wyardley, that's exactly the information I was looking for!

[edkrueger]

oolong is both partially oxidized and roasted.

Oolong is traditionally roasted,but it doesn't have to be. Currently, I belive most Gaoshan, TGY and Pouchong is unroasted.

[wyardley]

For Shu Pu-erh its picked, has its oxidation quickly stopped, piled up, wet, left alone for a few days, steamed and pressed.

Could be wrong here, but I think the length of this process is typically quite a bit longer than a few days, though a lot of the factories like to keep some of the specifics of their processes to themselves.

[wyardley]

ps - I see at least one suggestion online (in a post by one of our own forum members) that the microorganisms that are involved in the fermentation of shu cha are actually in the straw mats used to cover the piles of tea.

http://community.livejournal.com/puerh_tea/227607.html

I don't know how accurate that is, but that's one take.

Quote from IM with Jason (slightly reformatted):

To be honest, nobody knows if microorganisms are the primary agent in the aging of sheng tea. Some think the simple breakdown of the cell wall is most of it -- specifically from the low temp. kill green process not breaking down the enzymes*. Tests have just shown that there are microorganisms living in/on the tea, not that they do anything in particular.

* He mentioned in another conversation that the kill-green for pu'er may be done at a slightly lower temperature than for other "green" teas.

[Intuit]

While the fermentation process isn't strictly anaerobic (absence of oxygen), if the leaves are piled wet in a warehouse, the wet air within the leaf stack will be somewhat depleted of oxygen in a matter of days.

I kinda doubt this is true microbial fermentation of leaf starches; more likely its storage condition-regulated cellular breakdown of the leaves with a microbial assist.

The chemistry must be quite interesting, but it has zip to do with the original question of this thread, which pertains to the 'color' of tea/liquor.

Oolong is partially fermented/oxidized tea and is somewhere between a green and black, but has attributes different from these teas

Tea has a high degree of genetic variation; there is considerable genetic distinction between countries (Japan vs China and Kenya, for instance). Oolong varieties 'map' to each other (bear closer relationship to each other than to distant growing regions within China), when Guangdong Fujian (Wuyi) and Taiwanese oolongs are compared against one another by gene analysis. The Wuyi does appear to be among the oldest.

Genetic diversity among tea cultivars from China, Japan and Kenya revealed by ISSR markers and its implication for parental selection in tea breeding programmes.
http://www3.interscience.wiley.com/jour ... 1&SRETRY=0

Evaluation of genetic diversity in Oolong tea germplasms by AFLP fingerprinting.
http://www.cababstractsplus.org/abstrac ... 0043201268

I think what this could mean is that tea plants are reasonably 'plastic' in their ability to turn genes on and off according to the soil, climate, altitude and growing conditions (application of nutrients/fertilizer, seasonal temps/rains, harvest pressures, etc). This results in shifts in gene expression as a response to growing, harvest and processing conditions to afford certain definable and characteristic taste and odor qualities across tea types and more subtly within tea types that can be partially correlated to tea chemistry (caffeine, amino acids, polyphenols, volatile esters and aldehydes, etc) and professional taster / evaluator descriptions.

It explains how there can be so dashed many cultivated stable genetic lineages - a thousand or more and suggests why we might find some years producing more pronounced flavor tendencies within a fixed lineage (estate or garden).