Yeast in Raw Pu'er Tea?

[Noonie]

A question for someone who knows about food sensitivities / food science...

I am trying to determine if Yeast (brewers yeast, that contains Saccharomyces cerevisiae) exists in Raw Pu'er tea. I don't drink Ripe, so I'm not interested in anything concerning Ripe. I did a google search on "yeast pu'er tea" and found a few references, including from Hojo where yeast was mentioned with Ripe...and a lot about fermentation, then some scientific articles that were over my head. Hence why I'm here to ask my nerdy tea friends

I started drinking Pu'er in the last 4-6 months, and I've had a couple minor health issues since, including a urinary tract infection...which is all gone (note - I do not believe the tea I'm having is directly the cause, rather, some food sensitivity issues I already had but didn't know about...perhaps coupled me starting to drink Pu'er "may" have been a factor?). Before someone asks, these were quality teas (all samples) purchased from very reputable vendors. Some of the raw Pu'er I've had was from 2000-2005, a few close to the 10's, and more from 2013 to 2017. I'm having about 5-7g a day, most days (along with other teas I've drank for years...such as green and oolong).

I'm asking specifically about yeast because I recently had a food sensitivity test done (after one-and-off stomach/IBS issues for years, enough was enough ) and I had a really high sensitivity to both brewers and bakers yeast. So I want to try and cut those out, but not sure about Pu'er. When I started googling about yeast (oh no - don't take away beer or wine ), fermentation came up...and I thought...oh-oh, Pu'er is a fermented tea. Then I stopped making assumptions...and I'm here asking because I don't know about yeast/fermentation and Pu'er tea. Anyone here well informed?

Thanks in advance for reading the not-so-pleasant post, and for your insights.

[aet]

Im not a chemist , so can add only assumption. The sheng puerh is the name of the processing of the tea leaf. So I would google the Yeast in tea leafs. I would look up of what compounds the yeast is made of , from what compounds can be made and how. Then search if similar compounds are in the tea leaf or if the processing ( heat ) can produce such a compounds, consequently the yeast.
It is a little bit a homework alright, but only way how I see it making sense.
If there is any mention of yeast being in presence in shu puerh, I believe there will be some in aged or wet stored shengs as well. Because the key elements of transformation are same for both ( heat, moister , time ).

Do you have similar issues after drinking other teas? Have you tried dark oxidized black ( red ) tea ? What about the green teas? These are the closest by processing to the sheng puerh. Maybe try fresh sheng mao cha from 2019 , if afraid of astringency , might buy the autumn tea ( usually less astringent ) , or New concept processed sheng ( high temp. processed ) , has bit oolong type taste but most of the enzymes responsible for aging are killed.

[Noonie]

Thanks for the response. I’ve been drinking many varieties of green and oolong for years. Not a fan of black/red tea. I think the IBS is unrelated to tea as the test I did came up with lots of foods that I do eat where I have sensitivities (which I’ll be dropping). The test includes green and black tea and both were fine. Again, yeast was very high, so I’m researching that further as I want to understand further. The urinary track infection is first time, and the only think different in my eating/drinking is pu’er.

The article(s) I perused about pu’er had lots to say about fermentation with brief mention of yeast (under ripe, not raw). But that article wasn’t about yeast specifically, it was just mentioned.

Regarding homework, the little research I’ve done when searching ‘tea’, not specifically pu’er gave a lot about Kombucha.

[d.manuk]

There’s yeast all over fruits and generally everywhere in your environment, so I would say yes. Though if it’s the kind of yeast that is causing you issues it’s hard to say.

[Elise]

I’m not a specialist about this subject, but my feeling is that, as said Shine Magical, some type of yeast can be found everywhere.
As sheng pu’er can age and change over time, I would think yeast is part of the process but in a limited amount if the storage is rather dry. So if I wanted to limit (and not eradicate) consumption but still drink sheng, I think I would drink rather young sheng and favor dry storage.

[.m.]

It's not obvious to me that the naturally occurring yeast would survive the shaqing part of puerh processing. And its not very likely to survive the near boiling water used in brewing puerh. Can dead yeast still trigger some reaction? I dont know, but there are plenty of other things that can: mold spores, mycotoxins, etc., however these are typically associated with wet storage.

[Noonie]

Not sure if this helps clarify (with reference to yeast ‘everywhere’) but my sensitivities are to brewers and bakers yeast and that specific compound I mentioned above.

[NoahZwillinger]

Microbial and fungal communities exist within pu'er tea, and they change over time depending on the specific storage conditions. This study - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4918958/ - found species of Ascomycota fungi, a division of the fungi kingdom that baker's yeast is also a part of, present in both fresh leaf and raw pu'er samples.

I am not an expert, but since Saccharomyces cerevisiae is found within China (see here: https://www.nature.com/articles/s41467-018-05106-7), I would imagine it's a strong possibility that it could be present in raw pu'er tea. If it would be present to any meaningful extent in your circumstances I couldn't say.

[d.manuk]

Awesome post, new user @NoahZwillinger!

Maybe you can introduce yourself here?
viewtopic.php?f=2&p=16597#p16597

[Noonie]

Microbial and fungal communities exist within pu'er tea, and they change over time depending on the specific storage conditions. This study - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4918958/ - found species of Ascomycota fungi, a division of the fungi kingdom that baker's yeast is also a part of, present in both fresh leaf and raw pu'er samples.

I am not an expert, but since Saccharomyces cerevisiae is found within China (see here: https://www.nature.com/articles/s41467-018-05106-7), I would imagine it's a strong possibility that it could be present in raw pu'er tea. If it would be present to any meaningful extent in your circumstances I couldn't say.

Thank you!

[Stephen]

I think the article linked below (The Microbiome and Metabolites in Fermented Pu-erh Tea as Revealed by High-Throughput Sequencing and Quantitative Multiplex Metabolite Analysis) is a good one to understand the microbiology potentially present in puer tea. You mentioned wanting to avoid saccharomyces cerevisiae, a specific yeast otherwise know as brewers yeast and bakers yeast. The article doesn't show that particular yeast as being present in samples, but does mention other yeasts.

So the question becomes are you sensitive to other yeasts or only saccharomyces cerevisiae. It's also important to consider if you want complete avoidance (like an elimination diet) or to adjust your daily diet for better health (minimizing overall exposure to foods you might react to.) In that regard it could be helpful to compare the relative yeast exposure from tea to that from other foods (beer is probably higher!)

Speaking as a holistic healthcare and chinese medicine practitioner there is plenty more to say on the topic.