"Jon Nossen" writes:

"Lewis Perin" wrote in message
news
and it is possible that the caffeine content in buds is
lower than in leaves.

I don't think so, based on the small collection of numbers on
the Holy Mtn caffeine content page.

I'm not sure if that is a reliable source. Don't they state that
the teas they tested were made from tea bags? *Tea bags of white
tea*?

I'm unable to cerify those numbers independently, but I don't see
any reason to doubt them. I believe in tea-leaf freedom as much
as anyone, but I don't see why incarceration would invalidate the
caffeine figures.

Do tea bags with white tea actually exist? Seems like a very
strange animal to me.

Come to think about it, why are we worrying about tea bags? It looks
as if the teas whose caffeine content is listed on that Holy Mtn page
are all loose leaf (or Puerh tuocha etc.) teas from Holy Mtn.

According to the site, "The finely ground tea was extracted with
hot water."

The way I read this is, they ground up the leaves before doing the
caffeine measurements.

So is the amount of caffeine in white tea consisting of *whole
leaves or buds* similar to the amount in *finely ground* tea?
Just wondering.

Unless the grinding adds or subtracts caffeine, both of which seem
rather unlikely to me.

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

On Tue, 09 Mar 2004 12:25:23 -0800, Lewis Perin wrote:

"Jon Nossen" writes:

"Lewis Perin" wrote in message
news
and it is possible that the caffeine content in buds is lower
than in leaves.

I don't think so, based on the small collection of numbers on the
Holy Mtn caffeine content page.

I'm not sure if that is a reliable source. Don't they state that
the teas they tested were made from tea bags? *Tea bags of white
tea*?

I'm unable to cerify those numbers independently, but I don't see any
reason to doubt them. I believe in tea-leaf freedom as much as
anyone, but I don't see why incarceration would invalidate the
caffeine figures.

Do tea bags with white tea actually exist? Seems like a very strange
animal to me.

Come to think about it, why are we worrying about tea bags? It looks as
if the teas whose caffeine content is listed on that Holy Mtn page are
all loose leaf (or Puerh tuocha etc.) teas from Holy Mtn.

According to the site, "The finely ground tea was extracted with hot
water."

The way I read this is, they ground up the leaves before doing the
caffeine measurements.

So is the amount of caffeine in white tea consisting of *whole leaves
or buds* similar to the amount in *finely ground* tea? Just wondering.

Unless the grinding adds or subtracts caffeine, both of which seem
rather unlikely to me.

Is matcha ground up? The one used in the Japanese tea ceremony?

Dan Stromberg writes:

[...caffeine tests, tea bags, white tea, grinding leaves...]
Is matcha ground up? The one used in the Japanese tea ceremony?

Yes.

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

"Jon Nossen" writes:

[...bags, grinding, and caffeine...]

So is the amount of caffeine in white tea consisting of *whole
leaves or buds* similar to the amount in *finely ground* tea?
Just wondering.

Unless the grinding adds or subtracts caffeine, both of which seem
rather unlikely to me.

Not quite. The grinding makes sure that *all* the caffeine in
the leaves is extracted, as with Matcha tea, instead of an
amount *somewhat less* than that - of course, how much less will
depend on the particle size of the tea before grinding, the
water temperature and the steeping time.

Which is why I wonder how useful the stated caffeine amounts
really are.

I think they're useful as long as we're clear on what they are and
what they aren't.

They *are* a standardized (loosely speaking) measurement of caffeine,
applying the same measurement technique to all samples. That's the
reason they ground up the leaves, I'm sure.

They *aren't* a direct indication of how much caffeine gets into the
cup when you brew 2.0 grams of each tea "the right way", because "the
right way" will vary the temperature and steep time depending on the
type of tea. Let's not even think about how many "right ways" there
really are to brew a given type of tea!

What would make these measurements a lot more useful would be some
rules, however imprecise, for calculating caffeine uptake according to
brew temperature and steep time. A year or two ago on RFDT there was
an interesting thread ("Strong, Cheap, Black Tea") that made some
progress on this, but I think temperature was ignored.

Are you listening, Dog Ma?

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

What would make these measurements a lot more useful would be some
rules, however imprecise, for calculating caffeine uptake according to
brew temperature and steep time. A year or two ago on RFDT there was
an interesting thread ("Strong, Cheap, Black Tea") that made some
progress on this, but I think temperature was ignored.

Are you listening, Dog Ma?


Urrgh - I'm gonna regret this. But so are you, most likely. OK, here's a
chemist's take:

1. You're all correct.

1a. There are a lot of hidden variables here. E.g., the detailed history of
leaf preparation, like CTC vs. wither/toast, probably has a major effect on
the permeability of cell structures in the final product. If we consider
that broken leaf (unlike dust) is still mostly face with relatively little
edge, cell-wall permeability may matter a lotmore than sieve size.

2. That web site (like most) leaves out the most important datum any
scientist would demand first: experimental conditions. Alkaloid-content
measurements on everything from tea/coffee to opium and beyond have been SOP
for over a century. Usual deal is to dry the leaves thoroughly (and, to
pre-empt the question, these methylxanthine alkaloids are reasonably robust
to heat and air), finely grind, and extract with a hydrophobic solvent like
chloroform. Mixed alkaloids are then extracted into dilute aqueous acid,
leaving other organics in the solvent. The aqueous solution is basified,
alkaloids only (less sugars, tannins, etc.) re-extracted, usually into
ether. For tea, what's left is fairly pure theophylline, which can be
weighed up against starting leaf. If a precise number was needed, alkaloids
could be separated by liquid chromatography or fractional crystallization.
The foregoing is a few minutes' work in a going lab. (I know you didn't
really care, but I've done A LOT of these. And it's hard to forget, try as
one might; especially getting refused a coming-home kiss because of the
ether stink on one's breath.)

3. Nowadays, however, it can all be done far more accurately about three
minutes, with complete details of all the main soluble fractions, by
high-performance liquid chromatography.

4. Given the economic value of tea, somebody must have done a decent study
on this. However, as exemplified by an appallingly commercial and
scientifically corrupt article on espresso in a recent issue of Scientific
American, objectivity may be subverted.

5. There aren't all that many independent variables, as these things go. I
suspect that major levers a

- leaf size (e.g., whole, broken, fannings)
- fermentation history (none, halfway oolong, all-black)
- water temperature
- water purity (a low concentration of some ions can drastically reduce
solubility of organics, and possibly cell permeability as well)

all, of course, as a function of steeping time. Naturally, different tea
strains, parts, harvest times and plant maturities will all make a
difference. The above would permit some generalizations for extraction rates
of key flavor and physiology components for all teas.

6. That whole deal is about three days' work on equipment that's standard in
all sorts of academic, industrial and scientific labs. That's if run as a
full-factorial series, which no-one does anymore since experimental-design
software has shown the True Way. It would therefore be a dandy science
project for an advanced high-schooler or community college student. I'd have
done it myself years ago, but I kind of enjoy the mystery. And now I'm out
of the lab, so can't offer.

7. So back to (1) - who cares what the alkaloid or other
bioactive/organoleptic content of a leaf is? We want to know how much comes
out, and when, and how to get the personal best balance. And for that, the
perennial recommendation of {try new things, find people of discrimination
to recommend others, vary conditions to get the best from every tea} can't
be beat.

In a more or less unrelated note, since this post isn't yet long enough, has
anyone ever heard of white tea made by etiolation? (That's light-starving
plants to bleach them, as is done with asparagus.) Might be an interesting
effect. Especially since, or so I assume, many of the things we like best
about tea were put there by God and/or Darwin to keep animals from eating
the leaves.

-DM

"Dog Ma 1" (reply w/o spam) writes:

What would make these measurements a lot more useful would be some
rules, however imprecise, for calculating caffeine uptake according to
brew temperature and steep time. A year or two ago on RFDT there was
an interesting thread ("Strong, Cheap, Black Tea") that made some
progress on this, but I think temperature was ignored.

Are you listening, Dog Ma?

[...how a chemist would measure, plus lots of factors in cup caffeine...]

Thanks! That was instructive and interesting, but I should've made
clear what I was hoping for: for a given tea, some kind of formula for
caffeine extraction in 2 independent variables (temp and time.) The
particularity of the individual type of tea would be represented, I
suppose, by some constant (factors?)

In a more or less unrelated note, since this post isn't yet long enough, has
anyone ever heard of white tea made by etiolation? (That's light-starving
plants to bleach them, as is done with asparagus.) Might be an interesting
effect. Especially since, or so I assume, many of the things we like best
about tea were put there by God and/or Darwin to keep animals from eating
the leaves.

Hmm, are you hoping for even more confusion as to the meaning of
"white tea" than there already is out there?!

Gyokuro is shaded for at least part of its life; I don't suppose that
qualifies, does it?

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

"Lewis Perin" wrote:
Thanks! That was instructive and interesting, but I should've made
clear what I was hoping for: for a given tea, some kind of formula for
caffeine extraction in 2 independent variables (temp and time.) The
particularity of the individual type of tea would be represented, I
suppose, by some constant (factors?)

Right with you, bro. I've just never seen a comprehensive chart, table or
algorithm of the type you describe. Would be nice to have, for sure. It may
be that the leaf-processing and other variables I mentioned, or yet others,
make generalization impossible.

An earlier post to this NG or Teamail mentioned a "bell curve" for
extraction of various substances. Actually, it's much more complicated than
that. Whatever leaf is used, dissolution of surface exudates will be almost
instantaneous; hence the rapid coloring from EBT. For leaf contents, inward
diffusion of water and outward of solubles are highly non-linear, described
by complex partial differential equations, because degree of hydration
influences rate of further hydration. Then, over time, materials of lower
solubility and those buried deeper in plant tissue will elute at an
exponentially declining rate. So for any given material of interest, there
may be a surge in solution rate, a dip, a slower rise, and a gradual
fall-off. Every infusion will differ not only in total strength, but also in
balance. There's plenty of published work on efficient extraction of
valuable chemicals from plant matter, but that's usually a question of how
close they can get to total extraction, how quickly and how cheaply.

Sorry there's no simple answer, AFAIK. One almost-fact is that since the
alkaloids are relatively soluble in even warmish water, most of the
accessible theophylline and caffeine are probably out in a few seconds. I've
fooled around with completely hydrating leaves in cold water before that
first steep, and it seems to remove most of the caffeine (based on the
observation that I don't get my usual tea jitters) with nil loss of flavor
or color.

Hmm, are you hoping for even more confusion as to the meaning of
"white tea" than there already is out there?!

Absolutely. After all, as one of my profs used to say at every possible
occasion, erudition is not incontrovertibly predicated on obfuscation by
nugatory sesquipedalianism.

Gyokuro is shaded for at least part of its life; I don't suppose that
qualifies, does it?

Might well. My impression is that shade treatment of gyokuro is as much
about lightening the colour as anything. But I'm a philistine with limited
taste discrimination, so wouldn't know. I've never had a completely
etiolated tea, e.g. where branches were put in black plastic as soon as
leaves emerged. Seen this done for visual effect on greenhouse plants, and
it might make a very different taste. Who knows a plantation owner who'll
give it a try?

-DM

Dog Ma /10/04
reply w/o spam

[snipped passages from exchange between Lew and Dog Ma, sesquipedalian
surely but hardly nugatory]

...most of the
accessible theophylline and caffeine are probably out in a few seconds. I've
fooled around with completely hydrating leaves in cold water before that
first steep, and it seems to remove most of the caffeine (based on the
observation that I don't get my usual tea jitters) with nil loss of flavor
or color.

Happily read through the chemistry of this and especially your enlightening
previous post. (Two aspirin were sufficient to clear my head, -- I'm just a
poor country boy -- and so on we go.) Does my hoped for answer regarding
caffeine and theophilline -- that the second steep contains little or none
-- lie in the truth of your statements above? Is it really your considered
opinion that a few seconds of steep is sufficient to remove said elements?
Good news indeed.

Hmm, are you hoping for even more confusion as to the meaning of
"white tea" than there already is out there?!

Absolutely. After all, as one of my profs used to say at every possible
occasion, erudition is not incontrovertibly predicated on obfuscation by
nugatory sesquipedalianism.

Gyokuro is shaded for at least part of its life; I don't suppose that
qualifies, does it?

Might well. My impression is that shade treatment of gyokuro is as much
about lightening the colour as anything. But I'm a philistine with limited
taste discrimination, so wouldn't know. I've never had a completely
etiolated tea, e.g. where branches were put in black plastic as soon as
leaves emerged. Seen this done for visual effect on greenhouse plants, and
it might make a very different taste. Who knows a plantation owner who'll
give it a try?

I wonder if Ito En might point us in the right direction. They seem to have
a handle on these things. I think. Or maybe Nigel?

Michael

"Michael Plant" wrote
Two aspirin were sufficient to clear my head
Does my hoped for answer regarding
caffeine and theophilline -- that the second steep contains little or none
-- lie in the truth of your statements above? Is it really your
considered
opinion that a few seconds of steep is sufficient to remove said elements?


Glad to have contributed to your cardiovascular health - all us mature
people should take aspirin every day, as well as plenty of tea.

It's frustrating, because I could answer the alkaloid question easily,
quantatively and definitively for a whole range of teas and brewing types in
about an hour - if I still worked in the lab! Caffeine/theophylline are
about as easy to analyze as anything could be. (The other stuff is harder,
partly because it's not all single, well-defined compounds, and partly
because there's much less of it.)

I'm going to hazard a guess that for most teas, a few minutes in tepid water
will take out most of the alkaloids and not much else. That five seconds in
hot water will take out 90% from anything. And that in fannings/dust and
even small broken-leaf blacks, with most of the taste in dried surface
exudates, only cold water will remove buzz w/o taking away too much flavor.

That's an informed guess, because it's what I do. Too much caffeine just
keeps me awake at night; I only have a cup every month or two, and have a
low tolerance. Theophylline OD makes me quite ill. So if I'm having more
than one mug of strong Assam or one pot of sencha, I'll wash out most of the
theophylline per above. Cold water seems to work pretty well, though I have
yet to try it on expensive oolongs.

I'll ask around and see if anyone I know, or a student at the local
technical college, will do an evening's HPLC analysis (I'd provide the
samples) for the price of a sushi dinner - or perhaps a good gong-fu pot and
an ounce of Dan Cong.

-DM

Nice post, DM. Comments on two points:

Dog Ma 1 (reply w/o spam) wrote:
6. That whole deal is about three days' work on equipment that's standard in
all sorts of academic, industrial and scientific labs. That's if run as a
full-factorial series, which no-one does anymore since experimental-design
software has shown the True Way. It would therefore be a dandy science
project for an advanced high-schooler or community college student. I'd have
done it myself years ago, but I kind of enjoy the mystery. And now I'm out
of the lab, so can't offer.

Hey, factorial designs are nice if you want to know about all combinations
of conditions and types of tea. I presume that the goal of such an experiment
would not be to maximize the yield of caffeine.

In a more or less unrelated note, since this post isn't yet long enough, has
anyone ever heard of white tea made by etiolation? (That's light-starving
plants to bleach them, as is done with asparagus.) Might be an interesting
effect. Especially since, or so I assume, many of the things we like best
about tea were put there by God and/or Darwin to keep animals from eating
the leaves.

So that's what we Wisconsinites are - "etiolated". About this time of year
we all develop a kind of tint between ivory and light green.

The Japanese partially shade their Gyokuro, but that is to increase the
amount of chlorophyll. I suppose that the effect is nonlinear, with a bit
of shade making tea greener.

Best,

Rick.

"Dog Ma 1" (reply w/o spam) wrote in
message
...
I'm going to hazard a guess that for most teas, a few minutes
in tepid water
will take out most of the alkaloids and not much else. That
five seconds in
hot water will take out 90% from anything. And that in
fannings/dust and
even small broken-leaf blacks, with most of the taste in dried
surface
exudates, only cold water will remove buzz w/o taking away too
much flavor.

FWIW, I once found a research article on the web, where they had
analyzed how much of the main ingredients in tea bags were
extracted after 2 minutes steeping time. The results we

Caffeine: 55-90%
Flavonols and flavones glucosides: 55-90%
Flavanols (catechins), theaflavins and thearubigins: 35-55%

I unfortunately don't have the time to try to find the reference
or any more details, as in a few hours I will be heading for a
plane to take me to the land of Ceylon tea... Sri Lanka. Will
stay there for three weeks. Hopefully I will be able to visit a
tea plantation in the Nuwara Eliya district.

On Thu, 11 Mar 2004 02:25:07 GMT, "Dog Ma 1"
(reply w/o spam) cast caution to the wind and posted:

Sorry there's no simple answer, AFAIK. One almost-fact is that since the
alkaloids are relatively soluble in even warmish water, most of the
accessible theophylline and caffeine are probably out in a few seconds. I've
fooled around with completely hydrating leaves in cold water before that
first steep, and it seems to remove most of the caffeine (based on the
observation that I don't get my usual tea jitters) with nil loss of flavor
or color.

So, does this mean that most puerh is basically caffeine free,
considering that most preparation methods call for a rinse first?

Mike

"Dog Ma 1" (reply w/o spam) writes:

[...caffeine and steeping...]

I'm going to hazard a guess that for most teas, a few minutes in tepid water
will take out most of the alkaloids and not much else. That five seconds in
hot water will take out 90% from anything. And that in fannings/dust and
even small broken-leaf blacks, with most of the taste in dried surface
exudates, only cold water will remove buzz w/o taking away too much flavor.

I've just been trying to find some data on caffeine's extraction from
tea leaves as a function of steep temperature and time. (Using the
lazy man's research tool: Google.) Regarding temperature, there's
lots of talk about how lower steep temperatures slow down the
extraction, but not numbers.

A Canadian university student health pamphlet

http://www-health.concordia.ca/healt.../caffeine.html

cites these caffeine concentrations:

Tea (5 oz)

Brewed for 3 minutes--------------------------- 20-46

Brewed for 1 minute -----------------------------9-33

That is to say, after steeping 1 minute at an unspecified temperature
(but most people would assume near boiling) at least 11 to 13 mg of
caffeine is yet to emerge from the leaves.

A British government study

http://archive.food.gov.uk/maff/arch...144/annexc.htm

found that a 1-minute infusion from a teabag had 30% less caffeine
than a 5-minute infusion. They're talking about finely chopped leaves
here, and presumably very hot water, and still 30% remains after a
minute.

That's an informed guess, because it's what I do. Too much caffeine just
keeps me awake at night; I only have a cup every month or two,

Are you referring to coffee here? Or late-night tea?

and have a low tolerance. Theophylline OD makes me quite ill. So if
I'm having more than one mug of strong Assam or one pot of sencha,
I'll wash out most of the theophylline per above. Cold water seems
to work pretty well, though I have yet to try it on expensive
oolongs.

I'm a little dubious about cold water, because I actually use tepid
water a lot to brew tea in the summer. (I don't really like iced
tea.) I find that a 15-minute steep of a green yields a delicious cup
with no astringency at all, which gives a kind of creamy mouth feel.
I've no idea how much caffeine there is in the cup, but clearly a lot
of the good stuff in the leaves comes out in 15 minutes, so I'm not
sure I'd want to toss the liquor from a 5-minute steep in tepid water.

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

(Did we ever decide what what tea is, by the way?)

Peter


"Lewis Perin" wrote in message
news
"Dog Ma 1" (reply w/o spam) writes:

[...caffeine and steeping...]

I'm going to hazard a guess that for most teas, a few minutes in tepid
water
will take out most of the alkaloids and not much else. That five seconds
in
hot water will take out 90% from anything. And that in fannings/dust and
even small broken-leaf blacks, with most of the taste in dried surface
exudates, only cold water will remove buzz w/o taking away too much
flavor.

I've just been trying to find some data on caffeine's extraction from
tea leaves as a function of steep temperature and time. (Using the
lazy man's research tool: Google.) Regarding temperature, there's
lots of talk about how lower steep temperatures slow down the
extraction, but not numbers.

A Canadian university student health pamphlet

http://www-health.concordia.ca/healt.../caffeine.html

cites these caffeine concentrations:

Tea (5 oz)

Brewed for 3 minutes--------------------------- 20-46

Brewed for 1 minute -----------------------------9-33

That is to say, after steeping 1 minute at an unspecified temperature
(but most people would assume near boiling) at least 11 to 13 mg of
caffeine is yet to emerge from the leaves.

A British government study


http://archive.food.gov.uk/maff/arch...144/annexc.htm

found that a 1-minute infusion from a teabag had 30% less caffeine
than a 5-minute infusion. They're talking about finely chopped leaves
here, and presumably very hot water, and still 30% remains after a
minute.

That's an informed guess, because it's what I do. Too much caffeine just
keeps me awake at night; I only have a cup every month or two,

Are you referring to coffee here? Or late-night tea?

and have a low tolerance. Theophylline OD makes me quite ill. So if
I'm having more than one mug of strong Assam or one pot of sencha,
I'll wash out most of the theophylline per above. Cold water seems
to work pretty well, though I have yet to try it on expensive
oolongs.

I'm a little dubious about cold water, because I actually use tepid
water a lot to brew tea in the summer. (I don't really like iced
tea.) I find that a 15-minute steep of a green yields a delicious cup
with no astringency at all, which gives a kind of creamy mouth feel.
I've no idea how much caffeine there is in the cup, but clearly a lot
of the good stuff in the leaves comes out in 15 minutes, so I'm not
sure I'd want to toss the liquor from a 5-minute steep in tepid water.

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

Peter wrote:
(Did we ever decide what what tea is, by the way?)

Properly, steeped leaves from the tips of the branches of
the Camellia Sinensis bush.

Informally, steeped herbs of any kind.

--Blair
"'Texas Tea', f'rinstance."