I will make posters out of it and hang them in the gallery : ) Now case closed and could enjoy the finer meaning of good pu.
~ T
Sep 4th, '10, 09:13
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TIM
Re: Choosing a 7542
These are wonderful, Nick. Super!
I will make posters out of it and hang them in the gallery : ) Now case closed and could enjoy the finer meaning of good pu. ~ T
I will make posters out of it and hang them in the gallery : ) Now case closed and could enjoy the finer meaning of good pu.
~ TSep 4th, '10, 11:57
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Re: Choosing a 7542
nicolas, I thought you were joking at first about "puerh tea death." Those articles are about natural constituents of tea, not toxic pesticides or fertilizers. Most of them occur in all kinds of tea and other foods, and are not unhealthy. In fact, some of them, like epigallocatechin gallate and other flavonoids, are actually beneficial. Theoretically you can get ulcers from consuming large amounts of caffeine for a long time, but this doesn't really happen even to addicted coffee drinkers. Theanine, the other psychoactive component of tea, does not have negative effects and might even have some positive ones.
Only the first of those articles was relevant to your claims. To me (not a biochemist or doctor), it's unclear whether increased alanine aminotransferase and creatinine are signs of anything bad, and whether the results from feeding massive amounts of tea extract to rats tell us anything about the effects of normal tea drinking on humans. Maybe someone with expertise could tell us.
I'd be interested to know about the pesticide content of tea, since that does have the potential to do some harm. If pesticides really deteriorate over time, that would make aged pu'er better than all other tea. But there's a huge number of articles on pesticide residues in tea, so I won't be able to get through them any time soon.
Only the first of those articles was relevant to your claims. To me (not a biochemist or doctor), it's unclear whether increased alanine aminotransferase and creatinine are signs of anything bad, and whether the results from feeding massive amounts of tea extract to rats tell us anything about the effects of normal tea drinking on humans. Maybe someone with expertise could tell us.
I'd be interested to know about the pesticide content of tea, since that does have the potential to do some harm. If pesticides really deteriorate over time, that would make aged pu'er better than all other tea. But there's a huge number of articles on pesticide residues in tea, so I won't be able to get through them any time soon.
Sep 4th, '10, 17:59
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Re: Choosing a 7542
Acid does not equal harmful. Your stomach naturally makes hydrochloric acid at a pH of 2 to help digest your food. It also makes a protective mucous layer to keep that acid from digesting you from the inside out. Some acids may be harmful, but others, like vitamin C (ascorbic acid), are necessary for life.nicolas wrote: Phenolic acid, flavonoids, organic acids and esters, catechins, caffeine and o-methylated compounds.
I don't think I need to explain how acids can harm the bodyDrax wrote:1a. As part of this question, you should be able to answer how these chemicals act to do their damage.
So let's not lump all acids into the same boat. And flavenoids, included in the above list, are widely considered to be highly beneficial anti-oxidants.
As for the Wistar rat study re: tea extracts, I'd like to start by pointing out that 2500 mg/kg/day is the equivalent of 200 *grams* per day for a 70 kilo (150 lb) adult human. I can't see the entire article--don't have a subscription to the journal--so don't know how concentrated or dilute their tea extract is, but consider that 200 grams of tea is the equivalent of a couple of medium tuos or a smallish beeng of puerh.
How many of you consume half or a whole beeng of puerh daily?
Re: Choosing a 7542
Okay, I've read through all the abstracts (I wish I could read the whole articles, but even my membership with ACS doesn't cover that) plus some other articles, too. There's a great danger in only reading the abstracts -- in some of the articles, it was not clear whether "pu-erh" meant: raw, aged, or ripe. There's a lot of other critical info missing (which I'll talk about)
Bottom line -- I don't see anything that suggests young pu-erh to be bad. Or at least, if it is, then drinking Chinese green tea is just as bad. In all things moderation.
Let me address the concerns in the most obvious article - the one that looked at tea extract effects on rats (J Agric Food Chem, 2010, 58 (2), 1350-8.
The first problem is that without looking at the whole article, we have no idea what "Green Tea Extract" and "Black Tea Extract" actually mean. Did they just use boiling water? Did they use ethanol? (another study did use 75% ethanol for extraction) Did they use "normal brewing amounts?" or more? less? All these things will affect the concentration of the "extract." It's also unclear, then, if they reduced it at all (i.e. removed some water).
The next problem is the amount that they fed the rats. Now, this was explicitly supposed to be a high-dose study. But look at these amounts: 2500 mg/kg/day and 5000 mg/kg/day.
What does this mean? It means a rat was fed 2500 mg (or 2.5 grams) of extract per kilogram of its body weight every day (for 28 days in this study). For reference, I weigh 200 lbs, or 90 kg. This means I would be taking (2.5 * 90) = 225 grams, or (5.0 * 90) = 450 grams of extract every day. Now you can see why it's important to know what "extract" means. Is it 225 grams of a normal tea solution? (which is only about 7.5 oz... not a lot), or is it something else?
Finally the results -- "low toxicity." They used two assays that showed an increase in activity (they don't say how much it increased) -- as Mr. Usagi asks, does this mean liver damage? Well, the alanine amino transferase increase can be an indication of liver damage. But notice they say that the target organs were "considered" to be the liver and the kidney. In other words, it's a possibility. They do not mention an LD50 (lethal dose that kills half the population) -- in fact, it doesn't sound like any of the rats died at all (well, except maybe at the end of the study).
Of course, the real importance here is the comparison of the raw pu-erh with a fermented pu-erh, which under the same conditions, shows "no adverse effects...." That makes fermented pu "better."
We can't really resolve this one until we get a better definition of what "extract" meant. I am keenly aware of this problem, because a study just like this is why sassafras is banned from sale in the U.S. Somebody did a study with massively high concentrations on rats (equivalent of gallons per day) and the negative effects on the rats resulted in a ban.
But aside from the danger aspect, we talked about a number of other things. One of the other issues had to do with acids. The problem is that almost all of these frickin' compounds are acids. EGCG, catechins, and all the derivatives are acids (phenolic acids). But compared to ascorbic acid, citric acid, and a number of other acids common in food and our bodies, these phenolic acids are weak. You get to stronger acids when you start to talk about gallic acid, but according to at least two articles, gallic acids increases in pu-erh tea as it ages (which makes sense, and it would form from the oxidation of EGCG). This is nothing to worry about.
I noticed the introduction of an interesting term -- theabrownin. Only one source identified this term -- as "a group of water soluble polyphenols exhibiting brown color" (hence the name). In fact, one of these (the "-omics" 2-page paper) claims it's the major component of pu-erh. I would like to know more about this if possible. As best as I can tell, it is another word for ... tannins.
Which brings me to one of the missing pieces of all of these articles -- tannins. Or what you might call polymeric polyphenols. Here's a description of the chemicals in layman's terms. You've got gallic acid, and you've got flavone. Call them A and B. Catechins and all their ilk are derivatives (slight changes) to B. If you attach A to B (and make a few minor modifications) and you get the well-known EGCG (and all of its variations). If two of B dimerize (join together) you get theaflavin. There are lots of combinations, rather like lego blocks (you can even throw on sugars to these things), and they can keep forming really long links -- when they get big, those are what are collectively called tannins.
The problem with these really long chains of things -- they're hard to identify. Think of it this way. You've got all the building blocks A, B, and the slight changes (call them A', A'', B', B'', etc). It's "easy" to detect those because they're small and single units.
But when you start combining them (AA, AA', AB', AB'AB), each of these things is unique, and the possible combinations become staggering -- which is why the long chains just get called "tannins."
All of these studies appear to be using HPLC (high pressure liquid chromatography). For a quick description -- imagine sending a flood of people through an obstacle course. People have different sizes, and some have to hold hands as they go through. The smaller, quicker people will make it through first, while the larger, or linked people will take longer (as they get wrapped around something and have to disentangle, etc) -- a goofy description, but good enough. The researchers will have "standards" for comparison of the simple small building blocks (like EGCG, gallic acid, catechin, etc). But they won't for the more complicated combinations. In fact, having experience in this, I almost guarantee that all those many combinations all smear out as a nasty blob on their machine. Polymer-type compounds rarely play well on chromatography systems.
Bottom line on this tannin discussion -- they may be looking at the little bits left over when there are large structures sitting there that they're missing.
Very finally, as to the question of pesticides -- I would like to see a reference as to the break-down of these pesticides. One of the notorious things about pesticides is that they're often stubborn in degrading. We've come a long way since the days of DDT, or at least, we have in America.
Whew, well this was an interesting Saturday. I probably buried all my concerns in too many words.... but Nicolas, thanks again for all the interesting articles. I learned a lot. And most importantly, I learned not to worry.
edit: and I see while I was writing up this novel, debunix brought up the same points. Bingo!
Bottom line -- I don't see anything that suggests young pu-erh to be bad. Or at least, if it is, then drinking Chinese green tea is just as bad. In all things moderation.
Let me address the concerns in the most obvious article - the one that looked at tea extract effects on rats (J Agric Food Chem, 2010, 58 (2), 1350-8.
The first problem is that without looking at the whole article, we have no idea what "Green Tea Extract" and "Black Tea Extract" actually mean. Did they just use boiling water? Did they use ethanol? (another study did use 75% ethanol for extraction) Did they use "normal brewing amounts?" or more? less? All these things will affect the concentration of the "extract." It's also unclear, then, if they reduced it at all (i.e. removed some water).
The next problem is the amount that they fed the rats. Now, this was explicitly supposed to be a high-dose study. But look at these amounts: 2500 mg/kg/day and 5000 mg/kg/day.
What does this mean? It means a rat was fed 2500 mg (or 2.5 grams) of extract per kilogram of its body weight every day (for 28 days in this study). For reference, I weigh 200 lbs, or 90 kg. This means I would be taking (2.5 * 90) = 225 grams, or (5.0 * 90) = 450 grams of extract every day. Now you can see why it's important to know what "extract" means. Is it 225 grams of a normal tea solution? (which is only about 7.5 oz... not a lot), or is it something else?
Finally the results -- "low toxicity." They used two assays that showed an increase in activity (they don't say how much it increased) -- as Mr. Usagi asks, does this mean liver damage? Well, the alanine amino transferase increase can be an indication of liver damage. But notice they say that the target organs were "considered" to be the liver and the kidney. In other words, it's a possibility. They do not mention an LD50 (lethal dose that kills half the population) -- in fact, it doesn't sound like any of the rats died at all (well, except maybe at the end of the study).
Of course, the real importance here is the comparison of the raw pu-erh with a fermented pu-erh, which under the same conditions, shows "no adverse effects...." That makes fermented pu "better."
We can't really resolve this one until we get a better definition of what "extract" meant. I am keenly aware of this problem, because a study just like this is why sassafras is banned from sale in the U.S. Somebody did a study with massively high concentrations on rats (equivalent of gallons per day) and the negative effects on the rats resulted in a ban.
But aside from the danger aspect, we talked about a number of other things. One of the other issues had to do with acids. The problem is that almost all of these frickin' compounds are acids. EGCG, catechins, and all the derivatives are acids (phenolic acids). But compared to ascorbic acid, citric acid, and a number of other acids common in food and our bodies, these phenolic acids are weak. You get to stronger acids when you start to talk about gallic acid, but according to at least two articles, gallic acids increases in pu-erh tea as it ages (which makes sense, and it would form from the oxidation of EGCG). This is nothing to worry about.
I noticed the introduction of an interesting term -- theabrownin. Only one source identified this term -- as "a group of water soluble polyphenols exhibiting brown color" (hence the name). In fact, one of these (the "-omics" 2-page paper) claims it's the major component of pu-erh. I would like to know more about this if possible. As best as I can tell, it is another word for ... tannins.
Which brings me to one of the missing pieces of all of these articles -- tannins. Or what you might call polymeric polyphenols. Here's a description of the chemicals in layman's terms. You've got gallic acid, and you've got flavone. Call them A and B. Catechins and all their ilk are derivatives (slight changes) to B. If you attach A to B (and make a few minor modifications) and you get the well-known EGCG (and all of its variations). If two of B dimerize (join together) you get theaflavin. There are lots of combinations, rather like lego blocks (you can even throw on sugars to these things), and they can keep forming really long links -- when they get big, those are what are collectively called tannins.
The problem with these really long chains of things -- they're hard to identify. Think of it this way. You've got all the building blocks A, B, and the slight changes (call them A', A'', B', B'', etc). It's "easy" to detect those because they're small and single units.
But when you start combining them (AA, AA', AB', AB'AB), each of these things is unique, and the possible combinations become staggering -- which is why the long chains just get called "tannins."
All of these studies appear to be using HPLC (high pressure liquid chromatography). For a quick description -- imagine sending a flood of people through an obstacle course. People have different sizes, and some have to hold hands as they go through. The smaller, quicker people will make it through first, while the larger, or linked people will take longer (as they get wrapped around something and have to disentangle, etc) -- a goofy description, but good enough. The researchers will have "standards" for comparison of the simple small building blocks (like EGCG, gallic acid, catechin, etc). But they won't for the more complicated combinations. In fact, having experience in this, I almost guarantee that all those many combinations all smear out as a nasty blob on their machine. Polymer-type compounds rarely play well on chromatography systems.
Bottom line on this tannin discussion -- they may be looking at the little bits left over when there are large structures sitting there that they're missing.
Very finally, as to the question of pesticides -- I would like to see a reference as to the break-down of these pesticides. One of the notorious things about pesticides is that they're often stubborn in degrading. We've come a long way since the days of DDT, or at least, we have in America.
Whew, well this was an interesting Saturday. I probably buried all my concerns in too many words.... but Nicolas, thanks again for all the interesting articles. I learned a lot. And most importantly, I learned not to worry.
edit: and I see while I was writing up this novel, debunix brought up the same points. Bingo!
Re: Choosing a 7542
Are you the same nicolas that is offering Dayi 7542 (901) for sale on his website for $18 per cake?nicolas wrote:None of them.Tobias wrote:Which one would you recommend?
http://www.nicolastang.com/tea/online.html
Just checking, since you're telling the OP not to buy this tea.
Re: Choosing a 7542
Which goes to show that I do not have a vested interest in offering him that advice.zeusmta wrote:Just checking, since you're telling the OP not to buy this tea.
If he's buying it for immediate consumption (which is what I suspect the OP was asking), then my advice stands.
However it's fine to purchase it for aging and storage (many in China are doing it).
Last edited by nicolas on Sep 4th, '10, 21:40, edited 1 time in total.
Re: Choosing a 7542
Drax, I'm not suggesting that young plantation sheng is toxic, just that it's not something I drink regularly and would not recommend to anyone for regular consumption, especially to a beginner because I could not impress him with that young bitter 7542 experience and he would soon return to his green teas and oolongs. And for the same reasons, I would not recommend farmed salmon over wild caught salmon, or commercial eggs over organic eggs.Drax wrote: Whew, well this was an interesting Saturday. I probably buried all my concerns in too many words.... but Nicolas, thanks again for all the interesting articles. I learned a lot. And most importantly, I learned not to worry.
Here are some photos of farmed puerh bushes vs wild trees:
FARMED (aka 7542, 7532, 8582, 7572, 7562, 7262 etc)
WILD (aka Douji, Essence of Tea, Hailanghao, Xizhihao, Zhizhengtea etc)
150 year old puerh tree
Laobanzhang
Nannuo
Bangwai
(image courtesy of EoT)
Bulang
(image courtesy of EoT)
Manmai
(image courtesy of EoT)
Apart from the research reports which I cited (all of which are not on point because no one has conducted a specific study yet), there's a lot of other negative perspectives of young farmed sheng consumption from the traditional chinese medicine and nutrition data perspective, but I'll leave that out as I can't back that up with published medical research (only with folklore and hearsay).
Last edited by nicolas on Sep 7th, '10, 11:38, edited 1 time in total.
Re: Choosing a 7542
Hey nicholas, I went over to your site and checked out the three Chengsheng LBZ. The samples are all different prices and the cakes look different. In particular, the 2007 leaves look alot more beat-up and oxidized than the other years leaves.
When it came to Xizihao LBZ, I found the 2005 to have good thickness, but very subtle flavors and endurance around 12-16 brews. The 2006 LBZ Yan to be pretty thin, but robust, somewhat unbalanced flavors (and easy for me to taste!) with exceptional complexity and endurance of 20+. The 2006 Yin to be more balanced taste, but less interesting even if same endurance. These were all pretty different in the space of two years. How does the 2007, 2008, and 2009 LBZ compare to each other, in terms of the ChengSheng factory utilizing its modernized equipment? Not that I'd be buying any, I've got more LBZ than I could really afford, but I'm curious.
When it came to Xizihao LBZ, I found the 2005 to have good thickness, but very subtle flavors and endurance around 12-16 brews. The 2006 LBZ Yan to be pretty thin, but robust, somewhat unbalanced flavors (and easy for me to taste!) with exceptional complexity and endurance of 20+. The 2006 Yin to be more balanced taste, but less interesting even if same endurance. These were all pretty different in the space of two years. How does the 2007, 2008, and 2009 LBZ compare to each other, in terms of the ChengSheng factory utilizing its modernized equipment? Not that I'd be buying any, I've got more LBZ than I could really afford, but I'm curious.
Re: Choosing a 7542
Nicholas, thank you for bringing in this interesting discussion.Drax wrote:
There's a great danger in only reading the abstracts
Drax, I completely agree with you and sincerely thank you for enlightening us with more insight.
I still wonder if tea plants are so susceptible to pest or any kind of disease that farmers need to apply pesticide.
Sep 6th, '10, 15:10
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debunix
Re: Choosing a 7542
I would think any plant in monoculture is going to both strip the soil of the particular things that it requires more quickly--so need fertilizer--and attract whatever pests are going to go after it, in sufficient quantity to imperil the monoculture far more than the same plant grown interspersed with others like in the 'wild arbor' ancient plantations.
Re: Choosing a 7542
I know a little bit about breeding crop plants like wheat, maize and potato, but nothing about tea. Forgive me if I got it completely wrong.
My guess is tea probably an out breeding crop. Those plants they use in plantation very likely are the same clone, i.e. with identical genetics variation. The clone was selected base on favorable traits, like it is dwarf for easy harvesting, tend to branching out more so it will yield more buds, buds spouting uniformly, may be other factors like drought, pest and disease resistance. However, as they are all identical, it might do well with one particular strain of a particular disease, but fare poorly with the same disease but in different strain. As we all knew, the living world is never static, the organism which causes disease can have mutation. When you growing large number of cloned plants in close proximity, all it needed is a single mutated disease causing organism, and the disease will spread like wild fire. I think that is the reason why farming is such a difficult endeavor and why they needed so much chemical for intensive farming.
I think we are probably way off the original subject of choosing a 7542?
Well, in China any thing can happen, they might decided to have genetic modified pu'erh and called it 7542GM ...
My guess is tea probably an out breeding crop. Those plants they use in plantation very likely are the same clone, i.e. with identical genetics variation. The clone was selected base on favorable traits, like it is dwarf for easy harvesting, tend to branching out more so it will yield more buds, buds spouting uniformly, may be other factors like drought, pest and disease resistance. However, as they are all identical, it might do well with one particular strain of a particular disease, but fare poorly with the same disease but in different strain. As we all knew, the living world is never static, the organism which causes disease can have mutation. When you growing large number of cloned plants in close proximity, all it needed is a single mutated disease causing organism, and the disease will spread like wild fire. I think that is the reason why farming is such a difficult endeavor and why they needed so much chemical for intensive farming.
I think we are probably way off the original subject of choosing a 7542?
Well, in China any thing can happen, they might decided to have genetic modified pu'erh and called it 7542GM ...
Dec 12th, '10, 01:06
Posts: 749
Joined: May 2nd, '10, 02:03
Location: Shaker Heights, Ohio USA
Re: Choosing a 7542 The predicament of pu-erh in the West.
I am pretty new to the forum. However I have been drinking for about six years now with Dan Cong being my favorite.
Thanks for the recommendation for the 1993 Menghai 7542! I just bought 25 grams.
So many of us face the predicament of wanting to learn more about pu-erh, but not wanting to wait 30 years to do it!
1.Then if you start buying beens you get into real money.
2. How do you store it. For one, Cleveland/mid-west/northeast has got to be a terrible place to try to age pu-erh.
3. I have a *bunch* of young samples from YS. It is rough stuff! But has given me an idea of the spectrum that comes
4. I got some 35 year old pu-erh in San Francisco. Cannot compare to say whether or not it is good. Reminds me of turning over a pile of decomposing grass clippings. I served it to friends and they seem to enjoy it. My wife hates pu-erh. Will post photos later.
Seems like buying small samples is the way to go. It is an investment! How many of you have gone that route to learn about different cycles of pu-erh?
Thanks again. Great thread.
Hans
p.s. Death by young sheng...lol!
Thanks for the recommendation for the 1993 Menghai 7542! I just bought 25 grams.
So many of us face the predicament of wanting to learn more about pu-erh, but not wanting to wait 30 years to do it!
1.Then if you start buying beens you get into real money.
2. How do you store it. For one, Cleveland/mid-west/northeast has got to be a terrible place to try to age pu-erh.
3. I have a *bunch* of young samples from YS. It is rough stuff! But has given me an idea of the spectrum that comes
4. I got some 35 year old pu-erh in San Francisco. Cannot compare to say whether or not it is good. Reminds me of turning over a pile of decomposing grass clippings. I served it to friends and they seem to enjoy it. My wife hates pu-erh. Will post photos later.
Seems like buying small samples is the way to go. It is an investment! How many of you have gone that route to learn about different cycles of pu-erh?
Thanks again. Great thread.
Hans
p.s. Death by young sheng...lol!
If you'd like to experience what the tea might become in 15 years, you might try some samples from Essence of Tea:
[http://www.essenceoftea.co.uk/1993-7542.html]1993 Menghai 7542, at ~$1/g. A hopeful glimpse into the future, and a spectacular cup of tea.