On 22 Aug 2005 07:30:19 -0700, "Space Cowboy" >
wrote:

<major snippage and quoting>
>I think caffeine is directly proportional to taste. It is just another
>component that makes up tea taste. A weak tasting second cup means
>much less caffeine than the first. If multilple infusions hold up in
>taste then more caffeine in each cup.

Your argument is weak, my tea is not....
Here's Tea Chemistry 101:
The perceived flavor of tea is composed of many components. Each one
of these components has a different solubility rate; hence the longer
the leaf is in solution the more you will get out of the lower
solubility items, and conversely, the higher solubility components
will reach exhaustion earlier. Naturally, temperature will also affect
the rate of extraction. Some of the more commonly identified
components are as follows:
Flavonoids such as theaflavins and thearubigins
Polyphenol
Amino acids
Caffeine
Catechins are the tannins responsible for tea's astringency, and green
tea contains high concentrations. When green tea is fermented into
black tea, the catechin content diminishes.

Here is an interesting link describing the specific component and its
associated flavor note. Please notice that caffeine is not among them.
Caffeine is generally considered to add "briskness" but not flavor.
http://www.teatalk.com/science/compounds.htm
And another:
http://www.fmltea.com/Teainfo/tea-chemistry%20.htm
Also See Table 4.1(3)


>Most of the elements that make
>up tea taste are determined by leaching rates and not solubility.

Webster says: "Solubility: the extent to which one substance is able
to dissolve in another"
Webster says: "Leaching: intransitive verb; to lose soluble material
by dissolution"
Again, I ask what is the difference? Every bit of education I have
tells me that solubility is the relevant principle, and "leaching," as
you put it, is just another facet of solubility.


>So when we speak of caffeine water
>solubility that doesn't preclude a leaching rate which might be similar
>to the other taste components.

I do not disagree. It doesn't preclude other components from having
similar solubility, but that wasn't the point. The point with which I
disagree is your equation of a proportional relationship between taste
and caffeine, and I am challenging you to prove it with more than
loose assumptions. I believe there are many teas (most notably puerh)
that maintain a substantial, and, in some cases, preferable, amount of
flavor even after the caffeine is predominantly extracted.

"Due to the water-solubility of caffeine, much of it is extracted from
the leaf in the first 20-30 seconds of infusion, allowing you to
"decaffeinate" it yourself by steeping the leaves for approximately a
minute and discarding this first infusion. Then proceed as usual,
allowing slightly more time to achieve the desired strength.
(Employing this method, of course, will naturally sacrifice some
flavor.)" (2)


>It
>is the cultivar and not some given rate of caffeine solution for all
>teas. Duh.

Camellia Sinensis has caffeine levels of approximately 2.5 - 4%.
However, the distribution of caffeine in the plant depends on the part
of the plant from which it is derived. For example:
Bud 4.70 % First leaf 4.20 % Second Leaf 3.50 % Third Leaf 2.90 %
Upper stem 2.50 % Lower stem 1.40 %
Hence a large leaf green puerh can easily have less caffeine than a
tippy black puerh full of buds. These are facts, Jim, not assumptions
based upon subjective tastebuds.



>Caffeine is a stimulant that increases
>the absorbtion rate of taste. That is the upset empty stomach
>syndrome. If no caffeine not much tea taste.

Hmm. Please supply a reference for this as I don't buy it.


>Gongfu brewing
>essentially produces a saturated solution of caffeine and taste
>components which is consistent from infusion to infusion.

Here is where I will be subjective. I brew Gongfu style almost daily,
and that is a distinct change in the flavor nuances from steep to
steep. The flavor is not consistent but rather evolves as the steeps
progress. I have experienced this evolution of flavor from both puerh
and oolongs almost every time I brew them. The changes in
concentration between the different notes are definitely NOT linear.

>Otherwise
>the side effects of caffeine from the first cup would physically
>interfere with the subsequent tastings. The subtle taste of subsequent
>infusions can only be delivered by caffeine as a stimulant on the
>tastebuds.

Huh????? Are you saying I cannot taste subtleties without the presence
of caffeine? Blasphemy!

>The percentage of caffeine by weight
>argument in the first infusion doesn't carry much weight when applied
>to what we experience in the taste of tea. The caffeine by weight in
>solution is the exception and not the rule.

Seems to me it is a matter of chemistry, and in your case -
perception.



> Any statements like caffeine is more
>soluable than other taste componets is like saying the earth is flat to
>the horizion for a surveyor. It is a scientific factoid with no
>meaning to the amount of caffeine in your cup.

Back it up with proof please, and not subjective taste arguments.
Simply saying it over and over again doesn't make it so.


>If the caffeine is gone
>the taste is gone because the water solution rate is not fundamentally
>different than the leaching rates of other tasting components.

Hmm, me thinks science proves differently. Solubility of caffeine and
of tannins is very different.
This link shows the ratio differences in concentration of tea
components over time.
http://carcin.oxfordjournals.org/cgi...ll/24/2/263/T1
Even as early as 1900 they knew the extraction rates of caffeine and
tannins were different. This was before we learned of polyphenols and
the like.
http://www.ibiblio.org/herbmed/eclec...apter-vii.html


>The only reason tea taste different over time is the concentration of
>solution not the variability of the components. Proportionally they
>are the same in a weak cup versus a strong cup. The components of the
>taste are the same only different in concentration. The Gongfu method
>relies on saturation of all taste components for consistency in taste.
>The argument that there are fundamentally different dilution rates is a
>meaningless factoid when applied to taste. Take any tea you want, brew
>it according to any method you want, and it will essentially taste the
>same as any other method. The subsequent subtleties argument is
>nothing more than idiosyncractic personality quirks. The gongfu method
>can produce more infusions but the taste from a brown betty allowing
>for volume is the same that is you couldn't tell the difference if
>blindfolded.

Hmm, here is a quote from a leading journal.
"About 80% of Cr, Cu, Mn, Ni and Zn and 60% of Fe were in the first
infusion of a tea" (1)

>Next time don't pick my post
>apart unless you can reply with more evidence to back up any assertion
>be it scientific or anecdotal.

Hmm. He who lives in glass houses…….


>Don't make
>me get curt and accuse you of riding my coattails. If you know
>anything about tea change the subject and start your own thread.

Threatening now, are we?

>It isn't an
>academic argument perse

That's for sure….
So let's DO get academic then. All of this highly questionable
subjectivity is getting boring. Here are some more interesting links
for those who are interested:
http://home.netvigator.com/~aa321123/chemistry.html
http://www.dilmahtea.com/web/faq.asp
http://itech.pjc.edu/tgrow/2210L/chm2210LCafext.pdf
http://www.ansinet.org/fulltext/pjbs/pjbs63208-212.pdf
http://www.centurybio.com.cn/Tea_polyphenols.htm



References
(1)
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract
(2) http://www.imperialtea.com/about/FAQ.asp
(3) http://www.rirdc.gov.au/reports/NPP/04-033.pdf
See table 2.4- 2.5-4.1






Mike Petro
http://www.pu-erh.net
"In this work, when it shall be found that much is omitted, let it not be forgotten that much likewise is performed."
Samuel Johnson, 1775, upon finishing his dictionary.