Tea (rec.drink.tea) Discussion relating to tea, the world's second most consumed beverage (after water), made by infusing or boiling the leaves of the tea plant (C. sinensis or close relatives) in water.

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Old 29-10-2004, 08:15 PM
Robert Dunbar
 
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Default How much caffeine in Pu-er?

Does anybody know how caffeine is is Pu-er, compared to black, green and oolong?

Also, does "green Pu-er" have less caffeine than the regular stuff?

Robert

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Old 30-10-2004, 04:07 AM
Alex Chaihorsky
 
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Default

"Robert Dunbar" wrote in message
...
Does anybody know how caffeine is is Pu-er, compared to black, green and
oolong?

Also, does "green Pu-er" have less caffeine than the regular stuff?

Robert


All tea leaf have the same (appox) amount of caffeine. However it is easier
to extract it in one steep from broken leaf oxidized teas (like average
black) and therefore the cup of black tea has more caffeine than others.
Black tea is rarely re-steeped and if it is, the second steep has much less
caffeine. Whole leaf teas and large leaf teas have the same amount of
caffeine, but give it up slower (and not only caffeine, but all its
ingredients) and therefore are steeped several times. This way each cup may
have less caffeine. Steeping time and temperature also play their roles.

Puerh has the same amount of caffeine (by weight) and depending on
technology can give it up quicker and slower. Same while leaf vs broken,
temperature, steeping time etc. But nothing is better than direct
measurment. If you have a liquid chromatograph handy.

Sasha.


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Old 30-10-2004, 04:07 AM
Alex Chaihorsky
 
Posts: n/a
Default

"Robert Dunbar" wrote in message
...
Does anybody know how caffeine is is Pu-er, compared to black, green and
oolong?

Also, does "green Pu-er" have less caffeine than the regular stuff?

Robert


All tea leaf have the same (appox) amount of caffeine. However it is easier
to extract it in one steep from broken leaf oxidized teas (like average
black) and therefore the cup of black tea has more caffeine than others.
Black tea is rarely re-steeped and if it is, the second steep has much less
caffeine. Whole leaf teas and large leaf teas have the same amount of
caffeine, but give it up slower (and not only caffeine, but all its
ingredients) and therefore are steeped several times. This way each cup may
have less caffeine. Steeping time and temperature also play their roles.

Puerh has the same amount of caffeine (by weight) and depending on
technology can give it up quicker and slower. Same while leaf vs broken,
temperature, steeping time etc. But nothing is better than direct
measurment. If you have a liquid chromatograph handy.

Sasha.


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Old 30-10-2004, 03:26 PM
Mike Petro
 
Posts: n/a
Default


Puerh has the same amount of caffeine (by weight) and depending on
technology can give it up quicker and slower. Same while leaf vs broken,
temperature, steeping time etc. But nothing is better than direct
measurment. If you have a liquid chromatograph handy.

Sasha.


Different puers do indeed contain different amounts of caffeine and it
does appear that green puer is lower than most. See
http://www.holymtn.com/tea/teacaffeine.htm for more info. They used
reversed phase liquid chromatography with UV detection for their
study.

Caffeine is extremely water soluble. Most traditional methods of
brewing puer involve "washing" the tea, literally rinsing it one or
two times with hot, often boiling, water. I suspect that this is
tantamount to significantly decaffeinating the tea. While I have never
seen a study of available caffeine "after" washing, deductive
reasoning certainly supports this theory.


Mike Petro
http://www.pu-erh.net
remove the "filter" in my email address to reply


  #6 (permalink)   Report Post  
Old 30-10-2004, 03:26 PM
Mike Petro
 
Posts: n/a
Default


Puerh has the same amount of caffeine (by weight) and depending on
technology can give it up quicker and slower. Same while leaf vs broken,
temperature, steeping time etc. But nothing is better than direct
measurment. If you have a liquid chromatograph handy.

Sasha.


Different puers do indeed contain different amounts of caffeine and it
does appear that green puer is lower than most. See
http://www.holymtn.com/tea/teacaffeine.htm for more info. They used
reversed phase liquid chromatography with UV detection for their
study.

Caffeine is extremely water soluble. Most traditional methods of
brewing puer involve "washing" the tea, literally rinsing it one or
two times with hot, often boiling, water. I suspect that this is
tantamount to significantly decaffeinating the tea. While I have never
seen a study of available caffeine "after" washing, deductive
reasoning certainly supports this theory.


Mike Petro
http://www.pu-erh.net
remove the "filter" in my email address to reply
  #7 (permalink)   Report Post  
Old 30-10-2004, 04:43 PM
Alex Chaihorsky
 
Posts: n/a
Default

Two things, Mike:

1. "Different puers do indeed contain different amounts of caffeine"?
Common, Mike - 1.7 vs. 3.4% is statistically not a difference - although it
appear to be "twice", but it is only with a 1.7 total percent!. I am sure
they would get the same difference if they would measure not a one, but
several samples of the same tea with different temperatures!

2. The extraction from green teas is slower and the obly way to really
measure teh caffeine content is to do multiple steeps until there is no
caffeine left in teas and calculate the sum.

3. Caffeine is highly soluble, you are absolutely right. But you also have
to take into consideration that to enter solution it has first be extracted
from the dead cells of the tealeaf, and that takes time. And mechanical
properties of the tea play critical role in that delay. I very much doubt
that any significant portion of caffeine is extracted during short washing
period, because the leaves must first be saturated with water to expand and
this take time. I actually think that with puerhs and green teas the second
and the third steeps (especially the second) is the most caffeinated.

Sasha.



"Mike Petro" wrote in message
...

Puerh has the same amount of caffeine (by weight) and depending on
technology can give it up quicker and slower. Same while leaf vs broken,
temperature, steeping time etc. But nothing is better than direct
measurment. If you have a liquid chromatograph handy.

Sasha.


Different puers do indeed contain different amounts of caffeine and it
does appear that green puer is lower than most. See
http://www.holymtn.com/tea/teacaffeine.htm for more info. They used
reversed phase liquid chromatography with UV detection for their
study.

Caffeine is extremely water soluble. Most traditional methods of
brewing puer involve "washing" the tea, literally rinsing it one or
two times with hot, often boiling, water. I suspect that this is
tantamount to significantly decaffeinating the tea. While I have never
seen a study of available caffeine "after" washing, deductive
reasoning certainly supports this theory.


Mike Petro
http://www.pu-erh.net
remove the "filter" in my email address to reply



  #8 (permalink)   Report Post  
Old 30-10-2004, 08:18 PM
Mike Petro
 
Posts: n/a
Default


Common, Mike - 1.7 vs. 3.4% is statistically not a difference - although it
appear to be "twice", but it is only with a 1.7 total percent!.


50% more is indeed a difference in my book. Twice as much of a little
bit is still twice as much, just ask anyone who is susceptible to
caffeine jitters.


2. The extraction from green teas is slower and the obly way to really
measure teh caffeine content is to do multiple steeps until there is no
caffeine left in teas and calculate the sum.


I agree that since the extraction method is not listed here, beyond
the fact they used powdered leaf, that there is room for question. My
assumption is that anyone with access to this type of equipment would
know how to do a proper sampling, but that is only an assumption.



3. Caffeine is highly soluble, you are absolutely right. But you also have
to take into consideration that to enter solution it has first be extracted
from the dead cells of the tealeaf, and that takes time. And mechanical
properties of the tea play critical role in that delay. I very much doubt
that any significant portion of caffeine is extracted during short washing
period, because the leaves must first be saturated with water to expand and
this take time. I actually think that with puerhs and green teas the second
and the third steeps (especially the second) is the most caffeinated.


Possibly, I would love to see a proper study on it though. I cant help
but feel that hot water will dissolve a significant portion of the
caffeine immediately, but yes the second steep may indeed still
contain a considerable amount. However if you do 2 rinses, as is
popular with black puer, then where do we stand?

It is an old trick with black (aka red) tea that if you want to
decaffeinate it substantially all you need to do is steep it for 30
seconds and throw away the first infusion. The "washing tea" may not
be long enough to saturate the leaf totally but it is bound to have an
effect.

Mike Petro
http://www.pu-erh.net
remove the "filter" in my email address to reply
  #9 (permalink)   Report Post  
Old 30-10-2004, 08:18 PM
Mike Petro
 
Posts: n/a
Default


Common, Mike - 1.7 vs. 3.4% is statistically not a difference - although it
appear to be "twice", but it is only with a 1.7 total percent!.


50% more is indeed a difference in my book. Twice as much of a little
bit is still twice as much, just ask anyone who is susceptible to
caffeine jitters.


2. The extraction from green teas is slower and the obly way to really
measure teh caffeine content is to do multiple steeps until there is no
caffeine left in teas and calculate the sum.


I agree that since the extraction method is not listed here, beyond
the fact they used powdered leaf, that there is room for question. My
assumption is that anyone with access to this type of equipment would
know how to do a proper sampling, but that is only an assumption.



3. Caffeine is highly soluble, you are absolutely right. But you also have
to take into consideration that to enter solution it has first be extracted
from the dead cells of the tealeaf, and that takes time. And mechanical
properties of the tea play critical role in that delay. I very much doubt
that any significant portion of caffeine is extracted during short washing
period, because the leaves must first be saturated with water to expand and
this take time. I actually think that with puerhs and green teas the second
and the third steeps (especially the second) is the most caffeinated.


Possibly, I would love to see a proper study on it though. I cant help
but feel that hot water will dissolve a significant portion of the
caffeine immediately, but yes the second steep may indeed still
contain a considerable amount. However if you do 2 rinses, as is
popular with black puer, then where do we stand?

It is an old trick with black (aka red) tea that if you want to
decaffeinate it substantially all you need to do is steep it for 30
seconds and throw away the first infusion. The "washing tea" may not
be long enough to saturate the leaf totally but it is bound to have an
effect.

Mike Petro
http://www.pu-erh.net
remove the "filter" in my email address to reply
  #10 (permalink)   Report Post  
Old 30-10-2004, 10:10 PM
Lewis Perin
 
Posts: n/a
Default

Mike Petro writes:

[...]
It is an old trick with black (aka red) tea that if you want to
decaffeinate it substantially all you need to do is steep it for 30
seconds and throw away the first infusion. The "washing tea" may not
be long enough to saturate the leaf totally but it is bound to have an
effect.


The 30 second trick is indeed famous. It's been mentioned countless
times, but I don't recall ever seeing good numbers on what it achieves.

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


  #11 (permalink)   Report Post  
Old 30-10-2004, 11:21 PM
Alex Chaihorsky
 
Posts: n/a
Default

"Mike Petro" wrote in message
...

Common, Mike - 1.7 vs. 3.4% is statistically not a difference - although
it
appear to be "twice", but it is only with a 1.7 total percent!.


50% more is indeed a difference in my book. Twice as much of a little
bit is still twice as much, just ask anyone who is susceptible to
caffeine jitters.


Sorry, Mike, mathematics does not work this way. The 'twice" thing only
makes sense if the you first established that your standard variation is
significantly smaller. That can only be done on a number of measurements. If
they would have said that they measured several green puerhs of different
types and the caffeine content cluster around a certain number (plus/minus
standard deviation) and that cluster is significantly smaller or larger than
the cluster of black puerhs, then the numbers will make sense. Otherwise
they are senseless.



2. The extraction from green teas is slower and the obly way to really
measure teh caffeine content is to do multiple steeps until there is no
caffeine left in teas and calculate the sum.


I agree that since the extraction method is not listed here, beyond
the fact they used powdered leaf, that there is room for question. My
assumption is that anyone with access to this type of equipment would
know how to do a proper sampling, but that is only an assumption.



Mike, you know how I respect you, but thi sis very naive of you. You can
have access to LH at about $50/hour here in teh US or send the sample to the
lab from here to India for about $10/sample. The way they described their
experiment without multiple measurments, standard deviations and margins of
error (even political pollsters do that!) are self-evident.


3. Caffeine is highly soluble, you are absolutely right. But you also have
to take into consideration that to enter solution it has first be
extracted
from the dead cells of the tealeaf, and that takes time. And mechanical
properties of the tea play critical role in that delay. I very much doubt
that any significant portion of caffeine is extracted during short washing
period, because the leaves must first be saturated with water to expand
and
this take time. I actually think that with puerhs and green teas the
second
and the third steeps (especially the second) is the most caffeinated.


Possibly, I would love to see a proper study on it though. I cant help
but feel that hot water will dissolve a significant portion of the
caffeine immediately, but yes the second steep may indeed still
contain a considerable amount. However if you do 2 rinses, as is
popular with black puer, then where do we stand?


OK, let me put it this way - for a "wash" to work, the water has to
penetrate the insides of the dried cells of the leaf. The best indicator of
that is that the bulk of the leaf is not floating on the sirface anymore. So
put your puerh in hot water and measure the time when the bulk of the leaf
will settle on the bottom. This is the shortest possible time for caffeine
to be dissolved. But it also has to get out into the external part of the
solution. If you help it by say, centrifuge, I am quite sure that you will
get rid of 90% of caffeine. However as you know for non-boken or large leaf
tea to settle on teh bottom takes a LONG time. No 30-40 sek or even 1-3 min
wash would even come close.
Sorry, pal.

I would recommend a different experimental approach for the goal of decafing
a tea (based on extraction kinetics) - put it in ice-cold water until the
tea leaves sink (caffeine has a very high solubility - much higher than
other tea components) and ice-cold (or just cold) water will extract it with
no problem. Then, drain and brew (taking into consideration that it is
soaked in cold water, so you may need hotter water or even pre-heat the
soaked tea)


It is an old trick with black (aka red) tea that if you want to
decaffeinate it substantially all you need to do is steep it for 30
seconds and throw away the first infusion. The "washing tea" may not
be long enough to saturate the leaf totally but it is bound to have an
effect.


Exactly. See the above explanation and technique based on the "floating
time"

Sasha

Mike Petro
http://www.pu-erh.net
remove the "filter" in my email address to reply



  #12 (permalink)   Report Post  
Old 30-10-2004, 11:21 PM
Alex Chaihorsky
 
Posts: n/a
Default

"Mike Petro" wrote in message
...

Common, Mike - 1.7 vs. 3.4% is statistically not a difference - although
it
appear to be "twice", but it is only with a 1.7 total percent!.


50% more is indeed a difference in my book. Twice as much of a little
bit is still twice as much, just ask anyone who is susceptible to
caffeine jitters.


Sorry, Mike, mathematics does not work this way. The 'twice" thing only
makes sense if the you first established that your standard variation is
significantly smaller. That can only be done on a number of measurements. If
they would have said that they measured several green puerhs of different
types and the caffeine content cluster around a certain number (plus/minus
standard deviation) and that cluster is significantly smaller or larger than
the cluster of black puerhs, then the numbers will make sense. Otherwise
they are senseless.



2. The extraction from green teas is slower and the obly way to really
measure teh caffeine content is to do multiple steeps until there is no
caffeine left in teas and calculate the sum.


I agree that since the extraction method is not listed here, beyond
the fact they used powdered leaf, that there is room for question. My
assumption is that anyone with access to this type of equipment would
know how to do a proper sampling, but that is only an assumption.



Mike, you know how I respect you, but thi sis very naive of you. You can
have access to LH at about $50/hour here in teh US or send the sample to the
lab from here to India for about $10/sample. The way they described their
experiment without multiple measurments, standard deviations and margins of
error (even political pollsters do that!) are self-evident.


3. Caffeine is highly soluble, you are absolutely right. But you also have
to take into consideration that to enter solution it has first be
extracted
from the dead cells of the tealeaf, and that takes time. And mechanical
properties of the tea play critical role in that delay. I very much doubt
that any significant portion of caffeine is extracted during short washing
period, because the leaves must first be saturated with water to expand
and
this take time. I actually think that with puerhs and green teas the
second
and the third steeps (especially the second) is the most caffeinated.


Possibly, I would love to see a proper study on it though. I cant help
but feel that hot water will dissolve a significant portion of the
caffeine immediately, but yes the second steep may indeed still
contain a considerable amount. However if you do 2 rinses, as is
popular with black puer, then where do we stand?


OK, let me put it this way - for a "wash" to work, the water has to
penetrate the insides of the dried cells of the leaf. The best indicator of
that is that the bulk of the leaf is not floating on the sirface anymore. So
put your puerh in hot water and measure the time when the bulk of the leaf
will settle on the bottom. This is the shortest possible time for caffeine
to be dissolved. But it also has to get out into the external part of the
solution. If you help it by say, centrifuge, I am quite sure that you will
get rid of 90% of caffeine. However as you know for non-boken or large leaf
tea to settle on teh bottom takes a LONG time. No 30-40 sek or even 1-3 min
wash would even come close.
Sorry, pal.

I would recommend a different experimental approach for the goal of decafing
a tea (based on extraction kinetics) - put it in ice-cold water until the
tea leaves sink (caffeine has a very high solubility - much higher than
other tea components) and ice-cold (or just cold) water will extract it with
no problem. Then, drain and brew (taking into consideration that it is
soaked in cold water, so you may need hotter water or even pre-heat the
soaked tea)


It is an old trick with black (aka red) tea that if you want to
decaffeinate it substantially all you need to do is steep it for 30
seconds and throw away the first infusion. The "washing tea" may not
be long enough to saturate the leaf totally but it is bound to have an
effect.


Exactly. See the above explanation and technique based on the "floating
time"

Sasha

Mike Petro
http://www.pu-erh.net
remove the "filter" in my email address to reply



  #13 (permalink)   Report Post  
Old 30-10-2004, 11:21 PM
Alex Chaihorsky
 
Posts: n/a
Default

"Mike Petro" wrote in message
...

Common, Mike - 1.7 vs. 3.4% is statistically not a difference - although
it
appear to be "twice", but it is only with a 1.7 total percent!.


50% more is indeed a difference in my book. Twice as much of a little
bit is still twice as much, just ask anyone who is susceptible to
caffeine jitters.


Sorry, Mike, mathematics does not work this way. The 'twice" thing only
makes sense if the you first established that your standard variation is
significantly smaller. That can only be done on a number of measurements. If
they would have said that they measured several green puerhs of different
types and the caffeine content cluster around a certain number (plus/minus
standard deviation) and that cluster is significantly smaller or larger than
the cluster of black puerhs, then the numbers will make sense. Otherwise
they are senseless.



2. The extraction from green teas is slower and the obly way to really
measure teh caffeine content is to do multiple steeps until there is no
caffeine left in teas and calculate the sum.


I agree that since the extraction method is not listed here, beyond
the fact they used powdered leaf, that there is room for question. My
assumption is that anyone with access to this type of equipment would
know how to do a proper sampling, but that is only an assumption.



Mike, you know how I respect you, but thi sis very naive of you. You can
have access to LH at about $50/hour here in teh US or send the sample to the
lab from here to India for about $10/sample. The way they described their
experiment without multiple measurments, standard deviations and margins of
error (even political pollsters do that!) are self-evident.


3. Caffeine is highly soluble, you are absolutely right. But you also have
to take into consideration that to enter solution it has first be
extracted
from the dead cells of the tealeaf, and that takes time. And mechanical
properties of the tea play critical role in that delay. I very much doubt
that any significant portion of caffeine is extracted during short washing
period, because the leaves must first be saturated with water to expand
and
this take time. I actually think that with puerhs and green teas the
second
and the third steeps (especially the second) is the most caffeinated.


Possibly, I would love to see a proper study on it though. I cant help
but feel that hot water will dissolve a significant portion of the
caffeine immediately, but yes the second steep may indeed still
contain a considerable amount. However if you do 2 rinses, as is
popular with black puer, then where do we stand?


OK, let me put it this way - for a "wash" to work, the water has to
penetrate the insides of the dried cells of the leaf. The best indicator of
that is that the bulk of the leaf is not floating on the sirface anymore. So
put your puerh in hot water and measure the time when the bulk of the leaf
will settle on the bottom. This is the shortest possible time for caffeine
to be dissolved. But it also has to get out into the external part of the
solution. If you help it by say, centrifuge, I am quite sure that you will
get rid of 90% of caffeine. However as you know for non-boken or large leaf
tea to settle on teh bottom takes a LONG time. No 30-40 sek or even 1-3 min
wash would even come close.
Sorry, pal.

I would recommend a different experimental approach for the goal of decafing
a tea (based on extraction kinetics) - put it in ice-cold water until the
tea leaves sink (caffeine has a very high solubility - much higher than
other tea components) and ice-cold (or just cold) water will extract it with
no problem. Then, drain and brew (taking into consideration that it is
soaked in cold water, so you may need hotter water or even pre-heat the
soaked tea)


It is an old trick with black (aka red) tea that if you want to
decaffeinate it substantially all you need to do is steep it for 30
seconds and throw away the first infusion. The "washing tea" may not
be long enough to saturate the leaf totally but it is bound to have an
effect.


Exactly. See the above explanation and technique based on the "floating
time"

Sasha

Mike Petro
http://www.pu-erh.net
remove the "filter" in my email address to reply



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