Puerh Storage in Low Humidity

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Oct 21st, '09, 18:48
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Re: Puerh Storage in Low Humidity

by Intuit » Oct 21st, '09, 18:48

Thanks Pb2q. The entire Cha Dao series on Pu storage and aging should be standard reading for all pu-aging wannabes. Scott's comments as a major retail source in Asia, part i, are insightful, especially the comments on wetter vs dry aged sheng.

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Oct 22nd, '09, 09:34
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Re: Puerh Storage in Low Humidity

by xogget » Oct 22nd, '09, 09:34

Intuit wrote:Xogget, factory cakes have different leaves on the outside, right?

The working assumption has been that they're windowdressing, to pretty up the cake.

My assertion is that they're also inoculant, older leaves with established microbial community cultures; factory tea masters have their signature cultures used in annual recipe batches, probably matched more recently to leaf harvest origin, as a refinement. Thus, the large, exclusive contracting (mentioned in Nadas blog, for instance) of entire growing areas to a certain factory to ensure product consistency.
I didn't even realize the leaves on the outside are different!

Oct 25th, '09, 11:06
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Re: Puerh Storage in Low Humidity

by brose » Oct 25th, '09, 11:06

Intuit wrote:Here is from my perspective as an applied microbial ecology and civil engineering professional.
...
http://pubs.acs.org/doi/abs/10.1021/jf071629p
...
Thanks for the reference!

If you have anymore let me know, I have a decent primer from the ACS series of books on the subject of tea & caffiene as well as a few papers that analyze the general chemicals in tea.

After some fast research it appears that the rate of humidity for microbial growth is correlated linearly with the amount of microbes and presumably the rate of aging. For example if 50% humidity ages the tea in ~30 years then 25% humidity would take 60 years to have the same effect.
I'm not too bio savvy but can anyone confirm or deny this?

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Oct 25th, '09, 13:20
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Re: Puerh Storage in Low Humidity

by betta » Oct 25th, '09, 13:20

brose wrote: After some fast research it appears that the rate of humidity for microbial growth is correlated linearly with the amount of microbes and presumably the rate of aging. For example if 50% humidity ages the tea in ~30 years then 25% humidity would take 60 years to have the same effect.
I'm not too bio savvy but can anyone confirm or deny this?
Thanks for sharing the information.
I don't work with biological/microbial system, but as far as I know temperature might be the decisive factor in the aging. Humidity / water vapour might be only one of several prerequisites for the aging. Temperature determines whether the microbes will start to "digest" (age) the tea at an acceptable rate. Added to that the availability of free oxygen (in the air) in the storage environment is also important. Open up the storage container once for a while should help to maintain the oxygen content in storage condition at a good level for aging.

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Oct 25th, '09, 23:31
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Re: Puerh Storage in Low Humidity

by vibrantdragon » Oct 25th, '09, 23:31

You can raise the humidity in the local area just by storing your Pu'er in a cardboard box. Bring it out during the humid days and put it away when it gets dry and leave it boxed during the dry part of the year. That will help. I have seen many others talk about that, and I think some of the links others gave you talk about it. Just store like tea with like tea so you do not get too much cross contamination.

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Oct 27th, '09, 14:12
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Re: Puerh Storage in Low Humidity

by Maitre_Tea » Oct 27th, '09, 14:12

Guess I'll ask again, since this is kind of a big deal, and a deciding factor on whether I should make larger purchases:

So I live in southern California, where it's really dry and low on humidity. I don't have a pumidor yet because I'm going to be out of the country for the next few years, and I don't want to leave them in a pumidor going unchecked for a few years. But after I come back I'll move them to a more suitable environment, where they can age a little better. So, will my cakes begin to age normally or are they doomed forever?

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Oct 27th, '09, 16:24
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Re: Puerh Storage in Low Humidity

by tony shlongini » Oct 27th, '09, 16:24

brose wrote:After some fast research it appears that the rate of humidity for microbial growth is correlated linearly with the amount of microbes and presumably the rate of aging. For example if 50% humidity ages the tea in ~30 years then 25% humidity would take 60 years to have the same effect.
I'm not too bio savvy but can anyone confirm or deny this?

In the real world, such linear progressions are almost never the case.

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Oct 28th, '09, 14:27
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Re: Puerh Storage in Low Humidity

by betta » Oct 28th, '09, 14:27

Maitre_Tea wrote:Guess I'll ask again, since this is kind of a big deal, and a deciding factor on whether I should make larger purchases:

So I live in southern California, where it's really dry and low on humidity. I don't have a pumidor yet because I'm going to be out of the country for the next few years, and I don't want to leave them in a pumidor going unchecked for a few years. But after I come back I'll move them to a more suitable environment, where they can age a little better. So, will my cakes begin to age normally or are they doomed forever?
The best answer should be provided by people who live in your region, who are aging the cake naturally without artificially modifying the storage humidity and temperature.
My rough guess is if you really store it naturally at humidity lower than 80% and temperature below 32°C, you won't get mold grow over it.
Just check the weather history of your city last year to get a rough idea of the temperature and humidity fluctuation.
Again, like OMTP suggested, better to separate the cake individually in an envelope to make sure the airing is good and even to prevent "wet spot" which could lead to mold growth on the cake.

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Oct 28th, '09, 14:33
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Re: Puerh Storage in Low Humidity

by wyardley » Oct 28th, '09, 14:33

betta wrote:
Maitre_Tea wrote: So I live in southern California, where it's really dry and low on humidity. I don't have a pumidor yet because I'm going to be out of the country for the next few years, and I don't want to leave them in a pumidor going unchecked for a few years.
The best answer should be provided by people who live in your region, who are aging the cake naturally without artificially modifying the storage humidity and temperature.
My rough guess is if you really store it naturally at humidity lower than 80% and temperature below 32°C, you won't get mold grow over it.
His question is the opposite of what you're saying... Southern California is *very* dry, and so there's little or no danger of anything getting mold with natural storage.

The question is basically one which I don't think has been authoritatively answered (correct me if I'm wrong) -- that is, assuming that the microbial activity in pu'er tea stops or slows dramatically under too-low temperature / humidity, whether the microbial activity can start again once it stops.

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Oct 28th, '09, 14:44
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Re: Puerh Storage in Low Humidity

by Maitre_Tea » Oct 28th, '09, 14:44

wyardley wrote:
betta wrote:
Maitre_Tea wrote: So I live in southern California, where it's really dry and low on humidity. I don't have a pumidor yet because I'm going to be out of the country for the next few years, and I don't want to leave them in a pumidor going unchecked for a few years.
The best answer should be provided by people who live in your region, who are aging the cake naturally without artificially modifying the storage humidity and temperature.
My rough guess is if you really store it naturally at humidity lower than 80% and temperature below 32°C, you won't get mold grow over it.
His question is the opposite of what you're saying... Southern California is *very* dry, and so there's little or no danger of anything getting mold with natural storage.

The question is basically one which I don't think has been authoritatively answered (correct me if I'm wrong) -- that is, assuming that the microbial activity in pu'er tea stops or slows dramatically under too-low temperature / humidity, whether the microbial activity can start again once it stops.
+1

Exactly the question I'm hoping someone can answer, and maybe even offer a theory since there's little historical evidence of this, especially in such a dry place like Southern California.

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Oct 28th, '09, 16:37
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Re: Puerh Storage in Low Humidity

by AdamMY » Oct 28th, '09, 16:37

Let me preface this with I am not a biologist of any sort, but considering that things such as bread and such get moldy in most environments, I think its safe to say that there will always be microbes working in an environment that satisfies their needs.

Possibly a bigger question is, are the microbes naturally in the air in Say California or the America's in general, similar enough to the ones in china to get the same quality tea in 10-20 years time? And Should the cake freeze or be completely dried out (worst case scenario) When new microbes take root, will they have the same effect?

Now I can not speak as for dry aging in California, nor have I had any puerh long enough to judge aging in a Mid Atlantic climate, But I figure aging will always take place except under the extremist of conditions.

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Oct 28th, '09, 16:44
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Re: Puerh Storage in Low Humidity

by betta » Oct 28th, '09, 16:44

wyardley wrote: His question is the opposite of what you're saying... Southern California is *very* dry, and so there's little or no danger of anything getting mold with natural storage.

The question is basically one which I don't think has been authoritatively answered (correct me if I'm wrong) -- that is, assuming that the microbial activity in pu'er tea stops or slows dramatically under too-low temperature / humidity, whether the microbial activity can start again once it stops.
Ah.. I see.. I thought the issue is the mold growth which causes the cakes no longer edible.

Hm.. I don't think that the microbial activity will completely stop even after the cake is sterilized. There's always be contamination.
As far as I know, in the puerh processing the tea leaves are handfried "sha qing" and later steamed, which stops the further degradation in the leaves due to enzymes left in the leaves.
This heat treatment should actually kill microorganisms at the same time. Still, after processing the cake is what we can store for aging.
Maybe due to microorganism contamination after post-processing? :mrgreen:
I believe what ages the tea is fungus (mainly aspergillus niger) and therefore it takes relatively much longer time than if the aging is due to bacteria, but such a fungus is very...very... "robust".
In brief, it won't die so easily under "normal" atmospheric condition.
Imagine seeds of chili plant which are stored for 2 years in completely dry environment will grow after given proper condition.
Fungus' spores are even way more robust than regular chili seeds.
In fact I believe changes in the climate to regulate the microbial activity is beneficial.
We all heard about HK wet and relatively warm storage, which lead to smooth but less floral tea. There I think the microbial activity works at full speed throughout the year. In chemical process when something works at high speed and conversion, the side products and thus side effects will be larger.

Nov 25th, '09, 18:19
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Re: Puerh Storage in Low Humidity

by DocLogic77 » Nov 25th, '09, 18:19

Betta I think you are thinking along the right lines. If there is a sort of "sterilization" with processing it would be the mold that survives. Bacteria have nothing on mold spores which can survive unusually angry environments.

Nov 25th, '09, 19:06
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Re: Puerh Storage in Low Humidity

by Intuit » Nov 25th, '09, 19:06

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Last edited by Intuit on Nov 27th, '09, 23:01, edited 1 time in total.

Nov 25th, '09, 19:21
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Re: Puerh Storage in Low Humidity

by Intuit » Nov 25th, '09, 19:21

>Bacteria have nothing on mold spores which can survive unusually angry environments.

Ha! You haven't met my extremophilic bacterial buddies.
http://en.wikipedia.org/wiki/Extremophiles

:lol:

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