Dirt smell and taste in aged puer

Puerh and other heicha
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Octagon
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Sat Mar 16, 2019 3:35 pm

Hello everyone,

I recently picked up a cake of a Taiwan-stored puer from 2003 that has a strong dirt (geosmin) smell and taste. The cake is also quite "frosty" all the way through with white mold.

I don't have that much experience with more humid stored teas, I know MarshalN has mentioned white mold isn't all that uncommon to this type of tea and MattCha, who has reviewed this tea, does mention dirt in his tasting notes.

What would you guys say, is dirt smell and taste always a bad sign (of too aggressive storage) or is it just a particular style of more humid stored tea? I know a lot of western tea drinkers prefer dry-stored puer, but what I'm after is if there may be something wrong with the tea or if I'm just experiencing a bit of a culture shock, so to speak.
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debunix
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Sun Mar 17, 2019 12:56 am

I crave an earthy taste in puerh that reminds me of dirt, but in a good way: soft broken remains of leaves on a forest floor, rich well-treated garden earth, aged compost ready for spreading in the garden. 'Dirt' in that sense is a good thing.
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Baisao
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Sun Mar 17, 2019 1:58 am

The considerable amount of frostiness suggests improper storage. I have seen a bit of frost and it’s of little concern, but a lot of it would indicate that it got more wet than it should. I’ve had aged sheng from the 60s-70s that did not have this and they tasted impeccably clean: no dirt, barnyard, fish, mustiness, or other “off” aromas.

Dry-aged shengs from the 80s that I have tried were not ripe enough and were frequently still raw tasting. I mention this because I think some wet storage is helpful for sheng because even 35 year old dry stored sheng may not have changed enough for my liking.

It sounds like either an accident happened or someone rushed the aging.
minimastermike
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Mon Mar 18, 2019 11:20 am

Before you consider drinking it, look up the term "mycotoxicity". No matter what any tea blogger says on the matter, unless you know what kind of mold that is living on the tea, you should get rid of it even if its just a "little" moldy.
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Baisao
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Mon Mar 18, 2019 3:22 pm

minimastermike wrote:
Mon Mar 18, 2019 11:20 am
Before you consider drinking it, look up the term "mycotoxicity". No matter what any tea blogger says on the matter, unless you know what kind of mold that is living on the tea, you should get rid of it even if its just a "little" moldy.
@Octagon

https://www.who.int/news-room/fact-shee ... mycotoxins
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Stephen
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Mon Mar 18, 2019 3:37 pm

I think opinions vary on what's too much dirt smell and taste, and even how to define dirt smell and taste. What matters most is your personal preference. Opinions can also vary on what's too much "white frost." Some might say any is too much, while some find it acceptable on humid stored tea. Perhaps you can share a picture of the frost on the cake. Humid stored tea can also benefit from airing out (storing the tea whole or broken up in a drier environment.) This can reduce storage smells, dirt smells and even the white frost.
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Stephen
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Mon Mar 18, 2019 3:42 pm

Octagon
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Wed Mar 20, 2019 8:51 am

minimastermike wrote:
Mon Mar 18, 2019 11:20 am
Before you consider drinking it, look up the term "mycotoxicity". No matter what any tea blogger says on the matter, unless you know what kind of mold that is living on the tea, you should get rid of it even if its just a "little" moldy.
Sure, to not consume anything that's not known to be harmless seems sensible, but exploring puer tea is so much fun it's easy to stretch that and instead adopt a not-to-consume-anything-known-to-be-harmful-principle :D
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debunix
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Wed Mar 20, 2019 8:14 pm

thank you for an informative article. From the abstract:

...We characterized fungal and bacterial communities in leaves and both [raw and ripe/shou and sheng] Pu-erhs by high-throughput, rDNA-amplicon sequencing and we characterized the profile of bioactive extrolite mycotoxins in Pu-erh teas by quantitative liquid chromatography-tandem mass spectrometry....Major findings are: 1) fungal diversity drops and bacterial diversity rises due to raw or ripened fermentation, 2) fungal and bacterial community composition changes significantly between fresh leaves and both raw and ripened Pu-erh, 3) aging causes significant changes in the microbial community of raw, but not ripened, Pu-erh, and, 4) ripened and well-aged raw Pu-erh have similar microbial communities that are distinct from those of young, raw Ph-erh tea. Twenty-five toxic metabolites, mainly of fungal origin, were detected, with patulin and asperglaucide dominating and at levels supporting the Chinese custom of discarding the first preparation of Pu-erh and using the wet tea to then brew a pot for consumption.

That last sentence is very interesting. Time to discard those rinses regularly.
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Stephen
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Thu Mar 21, 2019 12:24 am

debunix wrote:
Wed Mar 20, 2019 8:14 pm
thank you for an informative article.
yes, very informative article! couple other interesting health related takeaways...

1) the tea itself may inhibit the production of mycotoxins and reduce mycotoxin toxicity.

"An explanation for finding fungi capable of producing mycotoxins, but not detecting the toxins themselves, may be found in a recent report that tea extracts inhibited aflatoxin production by Aspergillus flavus whereas they did not inhibit mycelial growth of the fungus [79]. Inhibition of mycotoxin production without inhibiting fungal growth was also reported for plants other than tea [80]. This situation might be the case for ochratoxin, as well. As noted above, to drink Pu-erh safely, most producers or distributers of Pu-erh tea recommend discarding the first brew, a practice that may be advisable to remove water-soluble or suspended contaminants."

"The discrepancy between our finding of high patulin concentration and the healthy reputation enjoyed by Pu-erh may be explained by the modulation of patulin toxicity through the action of green tea polyphenols."

2) some fungi produce compounds with potential health benefits

"Asperglaucide is reported to have anti-inflammatory effect and the ability to inhibit cysteine peptidases [48], which may be beneficial in protection against cartilage degeneration. Also detected in all samples was neoechinulin A, which has anti-inflammatory effects and can be produced by some Eurotium spp [67]. Fumigaclavine A, an antibacterial alkaloid produced by Aspergillus spp. [68] was detected in ripened tea only, while lotaustralin, a precursor to hydrogen cyanide [69], was detected in all samples of raw tea, but not in ripened tea samples. The fungicide cyclo(L-Pro-L-Tyr), produced by Lysobacter capsici [70] and Alternaria alternata [71], was detected in 60% and 100% of samples of raw and ripened tea, respectively, but in substantially higher amounts in ripened tea. This distribution was also the case for rugulusovin, which is produced by Penicillium spp. and has been shown to have cytotoxic effect against human and murine tumor cells."
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Baisao
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Thu Mar 21, 2019 1:01 am

"The discrepancy between our finding of high patulin concentration and the healthy reputation enjoyed by Pu-erh may be explained by the modulation of patulin toxicity through the action of green tea polyphenols."

I’m glad this section was called out as it seems nonsensical to me. In an otherwise good study this presumptive statement caused me to doubt the rest of their assertions. Specifically, where are the “green tea polyphenols” in shou or aged sheng? They will have rapidly broken down through oxidation, well before patulin was produced.
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Stephen
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Thu Mar 21, 2019 11:34 am

Just came across this article suggesting that pu er does have polyphenol content. Yes, that quote regarding patulin toxicity and polyphenols seems presumptive, unless there is other research out there on that topic.

https://www.tandfonline.com/doi/full/10 ... 16.1217877
minimastermike
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Fri Mar 22, 2019 7:47 am

Thanks for the interesting links!
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