Is Ripe Puerh Toxic?
This type of tea appears to be processed on concrete floors. Surely that would make the tea highly toxic, as the toxins from the concrete/cement would leach into the water on the floor and then move up by capillary action into the processed tea?
What toxins from the concrete? Concrete that isn’t pulverised is mostly inert.
I’m not a chemist but understand your point. I’ve seen many factories how the shu pu is made. And it’s not a "the cleanest " process alright. Some of them just leave it on concrete as u mentioned , but some of the would have tails or some special foil under. It’s hard to find out which company makes how, unless u go there your self or see some video or pics from blogs.
Why do you think that hardened concrete is “toxic” or leeches chemicals?
Generally the reason I stick to big factory and sellers I know for my puerh. I do know uncured concrete contains chlordane to harden it but I am not sure of the leaching after setting up.
The floor is seasoned with tea. A layer of wet tea is applied for several days before the batch as a starter. At the same time, most factories hold a finished batch for up to 3 years before pressing and selling to allow the tea to settle and air out. I’ve made shou myself more than once, and it is pretty smelly when finished, but 2-3 years later is a huge difference. Research shows that the microbial community of shou and sheng are nearly identical years on, the two types are more similar over time. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4918958/
That research article is familiar, one I’ve cited before in posts. I never interpreted them as saying the microbial community are nearly identical, only that they are similar (almost the same thing), and it’s hard to read the findings to be clearer on that since they’re not presented to emphasize that particular conclusion. Fermenting pu’er does result in the creation of toxins, probably more of a risk than the concrete. From that article conclusion: Fungal diversity drops and bacterial diversity rises as a result of raw or ripened fermentation. The composition of microbial communities changes significantly among fresh leaves, raw and ripened Pu-erh with the aged raw tea having similar community to ripened tea. Age of tea is identified as a significant variable affecting microbial community of raw tea, but not of ripened tea. Multiple mycotoxins were detected from either or both categories of Pu-erh, but all but patulin and asperglaucide were under the safety limit. For safe drinking, we recommend discarding the first brew.
Thanks to everyone for sharing their thoughts with me. If anyone has anything else to add to the conversation please feel free to join in.
I was reading a little online about concrete flooring and food hygiene, and although I’ve not had the time to get into it seriously, it seems as though, at least in the US and Europe, a floor is never considered hygienic for processing food. That sounds kind of obvious to me, I suppose. In factories where hygiene is paramount, industrial plant floors made of concrete have an additional polymeric screed applied; however, to be clear, the additional application of a polymer screed is there to help maintain general hygiene where people walk, and not a procedure that allows floors to be used for processing food.
I’ve heard of smaller companies using tarps to make ripe puerh, which might be safer; however, it all seems a little manky to me.
Maybe one day ripe puerh tea will be made in stainless steel vats.
I could buy an old cheese factory and convert the facilities so that ripe puerh tea can be made hygienically: The Stainless Steel Vat Ripe Puerh Tea Company.
The current trend is that more factories are making a transition to processing on pine wood which is elevated away from the concrete floor.
I’ve seen it in many factories already. I don’t think there’s any info on English sites. With the improving welfare, the demand in China is switching from ‘as cheap as possible’ to ‘quality’. Hygiene, is something local consumers care about, so naturally factories who have a long-term view, will eventually switch. Here’s an image:
The floor on the picture above is elevated, but you can’t really see it from the picture.