The greening of gongfu
 

For quite a while I've noticed that for lots of teas (e.g. young raw
Pu'er, most oolong, first flush Darjeeling) the color of the leaves
changes radically over the course of multiple steeps. Leaves that
when dry are some shade of brown (most of the above) or multicolored
(FFDJ, Oriental Beauty, some young shengs) gradually reach a uniform
shade of green. This shade of green differs from tea to tea, but the
direction of change over many steeps is the same.

I've never read anything about this, let alone an explanation. Is
there a clue, someone?

/Lew
---
Lew Perin /
http://www.panix.com/~perin/babelcarp.html
recent addition (thanks, corax): tianxia chacang

The greening of gongfu
 

On Jun 27, 2:03*pm, Lewis Perin > wrote:
> For quite a while I've noticed that for lots of teas (e.g. young raw
> Pu'er, most oolong, first flush Darjeeling) the color of the leaves
> changes radically over the course of multiple steeps. *Leaves that
> when dry are some shade of brown (most of the above) or multicolored
> (FFDJ, Oriental Beauty, some young shengs) gradually reach a uniform
> shade of green. *This shade of green differs from tea to tea, but the
> direction of change over many steeps is the same.
>
> I've never read anything about this, let alone an explanation. *Is
> there a clue, someone?
>
> /Lew
> ---
> Lew Perin /
> recent addition (thanks, corax): tianxia chacang

It's a really good question, one I've thought about too. Although I
don't drink many green oolongs there have been times when an oolong I
thought to be medium roasted and quite brown comes out a fairly
verdant green at the end. The only two theories I had ever come up
with in my mind were that either the oxidation/roasting was just very
superficial and "wore off" during the repeated brewings or that the
heating of the leaf somehow rejuvenates the leaf to become slightly
green again.

Those two theories are about as scientific as my socks, though, so I'm
sure one of the proper scientists will have the real story... I hope,
because I'd like to know too.

- Dominic

The greening of gongfu
 

On Jun 27, 2:03*pm, Lewis Perin > wrote:
> For quite a while I've noticed that for lots of teas (e.g. young raw
> Pu'er, most oolong, first flush Darjeeling) the color of the leaves
> changes radically over the course of multiple steeps. *Leaves that
> when dry are some shade of brown (most of the above) or multicolored
> (FFDJ, Oriental Beauty, some young shengs) gradually reach a uniform
> shade of green. *This shade of green differs from tea to tea, but the
> direction of change over many steeps is the same.
>
> I've never read anything about this, let alone an explanation. *Is
> there a clue, someone?
>
> /Lew
> ---
> Lew Perin /
> recent addition (thanks, corax): tianxia chacang

Lew
I've also noticed the same thing and wondered as well how something so
brown could turn so green. I've found this happens for medium oxidized
and/or medium roasted teas. For very roasted teas they usually stay
pretty dark. I was wondering if the oxidized portion of the leaf is
more water soluble since the liquor does turn brown. Hopefully someone
will have a more scientific explanation.

The greening of gongfu
 

My guess the depletion of chylophyll. Oxidation reduces chylophyll.
I judge a green tea from the color of the spent leaf. Indian oolongs
are essentially black. Chinese oolongs are essentially green.

Jim

Lewis Perin wrote:
> For quite a while I've noticed that for lots of teas (e.g. young raw
> Pu'er, most oolong, first flush Darjeeling) the color of the leaves
> changes radically over the course of multiple steeps. Leaves that
> when dry are some shade of brown (most of the above) or multicolored
> (FFDJ, Oriental Beauty, some young shengs) gradually reach a uniform
> shade of green. This shade of green differs from tea to tea, but the
> direction of change over many steeps is the same.
>
> I've never read anything about this, let alone an explanation. Is
> there a clue, someone?
>
> /Lew
> ---
> Lew Perin /
> http://www.panix.com/~perin/babelcarp.html
> recent addition (thanks, corax): tianxia chacang

The greening of gongfu
 

On Jun 27, 3:56 pm, TokyoB > wrote in response
to Lew's question:

> Lew
> I've also noticed the same thing and wondered as well how something so
> brown could turn so green. I've found this happens for medium oxidized
> and/or medium roasted teas. For very roasted teas they usually stay
> pretty dark. I was wondering if the oxidized portion of the leaf is
> more water soluble since the liquor does turn brown. Hopefully someone
> will have a more scientific explanation.

Here is a guess rather than an explanation, which would require a lab
assay.
Chlorophyll is insoluble in water (ref. Wikipedia, also my experience
with cooking). So I don't suppose
that the brown turns green but that the brown pigments are soluble,
leach out, and leave only
chlorophyll as a pigment. I note that most bright green tea leaves
don't yield a green liquor.
Now if you brew your tea in hot oil your results may be different.

Best,

Rick.

The greening of gongfu
 

writes:

> On Jun 27, 3:56 pm, TokyoB > wrote in response
> to Lew's question:
>
> > Lew
> > I've also noticed the same thing and wondered as well how something so
> > brown could turn so green. I've found this happens for medium oxidized
> > and/or medium roasted teas. For very roasted teas they usually stay
> > pretty dark. I was wondering if the oxidized portion of the leaf is
> > more water soluble since the liquor does turn brown. Hopefully someone
> > will have a more scientific explanation.
>
> Here is a guess rather than an explanation, which would require a lab
> assay.
> Chlorophyll is insoluble in water (ref. Wikipedia, also my
> experience with cooking). So I don't suppose that the brown turns
> green but that the brown pigments are soluble, leach out, and leave
> only chlorophyll as a pigment. I note that most bright green tea
> leaves don't yield a green liquor.
> Now if you brew your tea in hot oil your results may be different.

That makes sense to me as far as it goes. I think the red/brown
water-soluble pigments would be thearubigens and theaflavins. But how
would the green chlorophyll be either browned or masked in teas like
reds/blacks and cooked and aged raw Pu'er?

/Lew
---
Lew Perin /
http://www.panix.com/~perin/babelcarp.html