March BTL: Self-decaffeination

[Mary R]

Hey everyone!

Just a line to let you know that tomorrow's BTL is on self-decaffeination. I worked a slight jab on Dr. Weil and Mark 'Dr. Tea' Ukra in there, so I was happy.

I've just got a couple questions for all you ITD-ers.

First, I found my primary sources through Nigel's much-quoted expose on the topic--primarily the Hicks and Spiro papers. As I was putting the finishing touches on the article, though, it occurred to me that neither Hicks nor Spiro extrapolated the data down to the times that Nigel does.

I've not had the pleasure of talking to Nigel myself, but do any of you know why he did that? Does he have any source on the kinetics of infusion that justifies the numbers he came up with? The Hicks paper gives their first data point only after 5 min of infusion (at which point they say that an average of 69% of the caffeine left the leaves). The Spiro paper supposedly has its first data point at 90s with an average of 49% removal.

Nigel gives times down to 30 second for each, and the two extrapolations just don't match up with each other in the slightest.

Secondly, has anyone actually read the Spiro paper? It should be from

• Spiro, Michael. & others. (1981). 'Tea and the Rate of Its Infusion.' Chemistry in New Zealand 172-174.

I did everything I could to find it. I even went to the journal's site and tried to search. No luck. I google stalked Spiro out at the college he taught at and found a list of publications. "Tea and the Rate of Its Infusion" was not listed among them. (Other great ones were, though...and I can't wait to write a BTL on tea scum thanks to them!) Can anyone verify its existence?


**********************************************

Nigel's latest reincarnation of his post can be found at Cha Dao.

[tenuki]

Let me throw my ' off the top of my head' take on the Nigel article out there for fun:

I found the Nigel article interesting but somewhat suspect on the decaff question personally. Sure, 80% is probably a bogus claim, but to listen to him rant _no_ caffeine is removed in the first 5 minutes. There were too many bad assumptions and as you point out the math doesn't add up. In fact doing my own research from primary sources made it onto my 'todo' list after I read it. I got the feeling he had a belief he was supporting not that he was truly looking for the truth. The sections on variance due to farming techniques, ect was pretty good though, mostly because he actually included the facts and let them speak.

1) Without proof that the first 90 seconds is linear, extrapolation means nothing. the rest of the data clearly indicates a non-linear curve IMO (only 3% or so between 10-15 minutes...). Not only that, he discarded the figures from the study that stated 49% in the first 90 seconds - totally ignored them in his arguments, despite this being the closest to the brew times in question. I'm wondering why he even bothered to include them.

2) Water decaffeination _is_ used in the industry, depspite his 'logical' arguement which implied it wasn't. This was the first thing that alerted me that this was an axe grinding, not a fact finding mission. And yes, water decaffeination is a lot more involved than flash infusing tea for 30 seconds, but water _is_ used for decaffeination of tea and he implied it wasn't.

3) If you do a multiple short steep, the amount of caffein in any given steep is very small comparatively, and furthermore you start 'fresh' each brew. If 17% of the total ammount comes out in the first steep (my linear extrapolation based on the numbers, and my hunch it it isn't linear if you look at the data he provides from the hicks experiment) then the next steep logically would be as if the tea had 17% less total caffeen and you would only get 17% of that, etc. No mention of this is anywhere in the paper, so IMO it's crap.

100 of caffene:

1st steep - 17% of 100 = 17
2nd steep - 17% of 83 = 14
3rd steep = 17% of 69 = 12
4th steep = 17% of 57 = 10

53/100 in 4 steeps = 2 minutes
or, if you throw out the first brew...
36/100 in 4 steeps

Certainly far different than the 9% he claims and yes, also far different than 80% in the first 30 seconds, but this is with the linear assumption, which is clearly false if you look at the data.

I agree with him that any claim that 80% of the caffein comes out in the first 30 seconds is probably wrong, the article did debunk that I think, but I don't think it is the 9% he is claiming at one point in the diatribe.

bottom line - 80% in the first 30 seconds is clearly debunked, but I personally don't buy his 9%, it's probably closer to 30% for the typical gong fu cycle.

PS - try your public library Mary, they usually provide full article searches for free, mine does. This is usually the best way to find older stuff. Most of them use the EBSCO database and you can usually buy the article from another organization, I forget their name. My preliminary research actually found a very recent (2007) article on a study that used 30 second seep times. Here is the abstract...

TI- Effects of different steeping methods and storage on caffeine, catechins and gallic acid in bag tea infusions.
AF- Department of Health Diet and Restaurant Management, Chung Shan Medical University, Taichung, Taiwan.
AU- Yang DJ; Hwang LS; Lin JT
LA- English
SO- Journal Of Chromatography. A, 2007 Jul 13; Vol. 1156 (1-2), pp. 312-20. Electronic Publication
TA- J Chromatogr A
YR- 2007
MD- Print-Electronic
ME- Cited Medium: Print
EP- 2006 Dec 11
CY- Netherlands
IS- 0021-9673(Print)
PT- Journal Article; Research Support, Non-U.S. Gov't
JT- 9318488
SB- MEDLINE
MH- Food Handling*
MH- Caffeine/*analysis
MH- Catechin/*analysis
MH- Gallic Acid/*analysis
MH- Tea/*chemistry
MH- Chromatography, High Pressure Liquid/methods
MH- Temperature
AA- Y
AB- Bag teas, packed 3g of ground black, green, oolong, paochoung and pu-erh tea leaves (the particle size used was 1-2mm), were steeped in 150 mL of 70, 85 or 100 degrees C hot water to study the effects of the number of steeping (the same bag tea was steeped repeatedly eight times, 30s each time, as done in China for making ceremonial tea) and varied steeping durations (0.5-4 min) on caffeine, catechins and gallic acid in tea infusions. The changes in tea infusions during storage at 4 or 25 degrees C for 0-48 h and the variations in these compounds of bag tea infused with 150 mL of 4 or 25 degrees C cold water for 0.5-16 h were also investigated. A HPLC method with a C18 column and a step gradient solvent system consisting of acetonitrile and 0.9% acetic acid in deionized water was used for analysis. Results for all kinds of tea samples showed that the second tea infusion contained the highest contents of caffeine, catechins and gallic acid when bag teas were steeped in 70 degrees C water. It was different from that steeped at 85 and 100 degrees C, the highest contents existed in the first infusion. These compounds decreased gradually in later infusions. Higher amounts of caffeine, catechins and gallic acid could be released from bag teas as hotter water was used. As steeping duration prolonged, these ingredients increased progressively, however, their levels were lower than that cumulated from the infusions with the identical bag tea prepared recurrently at the same temperature and time points. (-)-Gallocatechin gallate and (+)-catechin existed in these tea infusions rarely and could not be detected until a certain amount of them infusing. Except gallic acid that showed a significant increase and caffeine that exhibited no significant change, all kinds of catechins decreased appreciably after tea infusions were stored at 25 degrees C for 36 h; nevertheless, all of them showed no evident changes at 4 degrees C storage. The caffeine, catechins and gallic acid in tea infused with cold water also increased with increasing duration. Their contents in 25 degrees C steeped tea were higher than that made at 4 degrees C; moreover, their infusion rates from bag teas to cold water were markedly lower than that steeped in hot water. Infusing efficiencies of non-gallated catechins were higher than gallated catechins under cold water steeping.
RN- 0 (Tea)
RN- 149-91-7 (Gallic Acid)
RN- 154-23-4 (Catechin)
RN- 58-08-2 (Caffeine)
LR- 20071115
EM- 20070625
DA- 20070925
UD- 20071207
PM- 17161409

[ABx]

Mary, one thing that I would love it if you'd do is to get ahold of someone that can give you some real information about how caffeine is extracted from anything using water, and maybe some differences in things like materials, temperatures, etc. Maybe a chemistry professor? This may not give you direct answers, but it could well give you a really solid foundation on which to start and could even shed some light on other subjects.

You could also talk to the folks at http://www.teascience.org/ and maybe check out some of their publications if you can find them in a library or something (they write for the industry, so there is likely to be some very solid info there).

[Mary R]

I did try my public library, and they refused to do any journal searches. Also, any time I've inter-library loaned anything through them, I've had a minimum wait time of 2 months to get my stuff. At DePauw, I usually got stuff within a week (though one CD from Alaska *did* take a month...).

Sigh. One of these days I'll take a road trip to my alma mater and have me a grand old time.

[ABx]

I did try my public library, and they refused to do any journal searches. Also, any time I've inter-library loaned anything through them, I've had a minimum wait time of 2 months to get my stuff. At DePauw, I usually got stuff within a week (though one CD from Alaska *did* take a month...).

Sigh. One of these days I'll take a road trip to my alma mater and have me a grand old time.

You might see about their book "Global Advances in Tea Science" (1999 Book 1: Global Advances in Tea Science. Ed. N.K. Jain. Aravalli Books International, New Delhi -110020.)

Amazon has it, but it's over $100 the last time I checked. I plan on buying it myself someday, but unfortunately that won't be in the immediate future.

[tenuki]

I looked into the tea science publication, but it seemed mostly slanted at growing tea and agricultural factors that influence production, rather than brewing, etc.

[scruffmcgruff]

Nigel didn't use a linear distribution, AFAIK:

...both sets of data look like a classic second order
quadratic response to me - and caffeine does not not suddenly become
100% soluble at 176 deg F, neither (in the real world) does a "wash"
with water at boiling point take place at 212 F. But, as Professor
Ingolfsson remarked (about polar bear ancestry): "This is just how I
interpret it. This is science - when you have little data, you have
lots of freedom."

This was taken from an RFDT discussion, written before that article.

Also, tenuki, it's not that I don't believe you, but where is the water-decaffeination process used? Nigel runs Teacraft, and is heavily involved and knowledgable in the production of tea (though this doesn't mean he knows *everything*).

[tenuki]

Nigel didn't use a linear distribution, AFAIK:

...both sets of data look like a classic second order
quadratic response to me - and caffeine does not not suddenly become
100% soluble at 176 deg F, neither (in the real world) does a "wash"
with water at boiling point take place at 212 F. But, as Professor
Ingolfsson remarked (about polar bear ancestry): "This is just how I
interpret it. This is science - when you have little data, you have
lots of freedom."

This was taken from an RFDT discussion, written before that article.

Also, tenuki, it's not that I don't believe you, but where is the water-decaffeination process used? Nigel runs Teacraft, and is heavily involved and knowledgable in the production of tea (though this doesn't mean he knows *everything*).

Dude, you need to take your Nigel colored glasses off - He did use an linear fit to extrapolate 3 minute data into 30 second data, the quadratic he used is essentially linear during that portion of the data, ie it is for all practical purposes linear out to around 4-5 minutes or so. His choice of that 'fit' is a convenient fiction.

That is why 9+9 = 18 ( 30 sec, ver 1 minute, vs 34 for 2 minutes (ie 9x4 =36). You can do that sort of basic math can't you? But what is really telling is his extrapolation of the spiro data... half of the caffeine is out in 90 seconds, yet his extrapolation doesn't try to fit that curve at all IMO.

Here is one source describing water decaffeination for tea...

http://www.nottinghall.com/decaffination.htm

But please, don't take my word for it, do your own research. I'm not disagreeing with his general idea, just pointing out grounds for having a healthy skepticism. I found it highly ironic that he decries the promulgation of opinion as fact, then does a less than stellar job of not falling into that trap himself.

Appeals to authority mean nothing to me, as I'm sure my dad would be happy to tell you.

[Space Samurai]

[Mary R]

Now THIS is a conversation!

[scruffmcgruff]

Damn tenuki, calm down. I was just relaying some basic info I wasn't sure you had.

I wasn't appealing to authority, I was just saying he has real life experience in tea production. Sorry you're so sensitive about it, but would you trust Dr. Tea over a Chinese tea master on matters relating to fine teas?

Your asshole comment about my math skills was out of line. You know very well that my lack of caring is what caused me to not crunch the numbers, not a lack of multiplication skills, so don't be a baby about it.

I don't think he doubts that his extrapolations aren't perfect (I did as well, as you can see by reading my previous comments on the subject in rfdt, if you want to see me without my "nigel colored glasses" on). Like he says, he's just using what he's got.

Also, the high-pressure water decaffeination your link describes is indeed quite different (doesn't seem to be a "simple and inexpensive process that removes 80% of caffeine in 30 seconds") from the infusing Nigel talks about, so I don't quite see where your argument is coming from, other than finding another way to "axe grind" his post.

Conclusion: Is Nigel's research and interpretation perfect? Probably not-- I doubt it would pass peer reviewing-- his extrapolation curve choice is a pretty heavy assumption. Is there a better interpretation of widely available research data out there? Not that I've seen.

[Edit: Sorry if I took your response more personally than was intended-- I realize you may not have intended to be insulting.]

[Chip]

WOW...what have I been missing.

Peace out my TeaBrothers.

To be honest, I respect both of you too much to see this continue.

So, shake hands and have a cup of TEA...maybe decaf? Quick before someone starts calling for group hugs....

[tenuki]

awe come on chip, if you can't be grumpy with family what's the point of living?

[tenuki]

would you trust Dr. Tea over a Chinese tea master on matters relating to fine teas?

Answer is neither. I would look for scientific data. 'experts' are wrong all the time. Look at all the experts claiming 80% decaf from a 30 second boiling wash....

Your asshole comment about my math skills was out of line. You know very well that my lack of caring is what caused me to not crunch the numbers, not a lack of multiplication skills, so don't be a baby about it.

ad hominem. not a valid argument, moving on.

Also, the high-pressure water decaffeination your link describes is indeed quite different (doesn't seem to be a "simple and inexpensive process that removes 80% of caffeine in 30 seconds") from the infusing Nigel talks about, so I don't quite see where your argument is coming from, other than finding another way to "axe grind" his post.

I was referring to the assumption many gullible people would make from his subtle and deliberately incorrect inference that water was not used to decaffeinate tea. Something _you_ obviously fell for so don't play innocent with me about that for the sake of your argument.... I would bet you money Nigel knows that there is a water process to decaffeinate tea but it didn't serve his argument, so he didn't mention it.

[ABx]

Mary - One thing I think might be worth mentioning in your article is the difference in effect between tea and coffee.

I think a lot of people decide to get away from caffeine because of coffee. With the L-Theanine (and probably more) to counterbalance it, and possible binding with polyphenols (if that's what it was) to make it slower to metabolize (if that's true, I don't know), the undesirable effects from caffeine really become much less of an issue. It's just been my experience that the caffeine really isn't so much an issue when it comes to tea, so readers may want to consider whether it's really worth trying. My reaction to people choosing decaffeinated green tea has always been "Why?", and my advice is generally to just find some better tea.