Pu erh tea aging and storage
ฝัง
- เผยแพร่เมื่อ 23 ก.ย. 2024
- Tea ages thanks to the combined action of enzymes and microorganisms. This video introduces the basic concepts behind tea aging and discusses how storage conditions influences aging.
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References:
S. Jayaratnam, D. Kirtisinghe. THE EFFECT OF RELATIVE HUMIDITY AND TEMPERATURE ON MOISTURE SORPTION BY
BLACK TEA. Tea Research Institute of Sri Lank 1974
Takeo T. Studies on the Changes of Polyphenol Oxidase
Activity during Black Tea Manufacture, Agr. BioI. Chern., Vol. 30, No.6, p. 529-535, 1966
YOSHITOMI H. Equilibrium Moisture Content of Tea Leaves
and Stems for Tea Manufacture. National Research Institute of Tea, 1985
Ming Zhao, Dong-lian Zhang, Xiao-qin Su, Shuang-mei Duan, Jin-qiong Wan, Wen-xia Yuan, Ben-ying Liu, Yan Ma & Ying-hong Pan. An Integrated Metagenomics/Metaproteomics Investigation of the Microbial Communities and Enzymes in Solid-state Fermentation of Pu-erh tea. World Journal of Microbiology and Biotechnology
2013, Vol 29, Issue 10, pp 1877-1884
Ming Zhao, Dong-lian Zhang, Xiao-qin Su, Shuang-mei Duan, Jin-qiong Wan, Wen-xia Yuan, Ben-ying Liu, Yan Ma & Ying-hong Pan. An Integrated Metagenomics/Metaproteomics Investigation of the Microbial Communities and Enzymes in Solid-state Fermentation of Pu-erh tea. doi:10.1038/srep10117, 2015
Chen A, Chen H-Y, Chen C. Use of Temperature and Humidity Sensors to Determine Moisture Content of Oolong Tea. Sensors (Basel, Switzerland). 2014;14(8):15593-15609. doi:10.3390/s140815593.
William is my absolute favourite source when it comes to tea. It's very seldom that you find somebody with such in-depth knowledge that still takes the time to humbly back up his claims and opinions with scientific papers, even though his opinion would be heard anyways at this point. Especially in the Pu'er community where everything's so opinion based. Compared with other western facing vendors he doesn't just source tea but also produces tea, so I know that I can actually trust him whenever he sources material from other teagardens that it's gonna be a great value!
Stellar and crystal clear scientific explanations for once. Thanks a lot!
Thank you for releasing such quality content - a very rare gift to the puerh drinking community.
Finally something i can understand and not have to question every sentence!
A proper tea-geek video. I love it!!! :D
Very impressive scientific content!
Excellent video, thank you. Special thanks for including references.
Best wishes
Thank you for watching!
Excellent and informative! Thank You!
please export your future videos in "mono" audio. the left channel in most of your videos are very soft
Absolutely interesting, William, I took your 3 Pu Erh Cakes in nice wooden Boxes with the Shu in a separate Box, and now I will taste the Weng Bo trial-package you laid in. Thank you very much for your good work. Denis.
You mentioned 40°C as maximum enzyme activity, where did you find this info? Also, it would be great if you could one day show pictures/video of leaves which you consider too red, too green, and intermediate. Many thanks!
Check figure 5 of this paper:
www.tandfonline.com/doi/pdf/10.1080/00021369.1966.10858642
What are your thoughts on humidity in aging white tea?
I keep my tea cakes in clay pot storage. This protect it from sunlight, humidity and keeps it dry & cool.
Just received some samples and a small cake from you guys, looking forward to tasting.
I hope you will lke the teas
Another great video - thanks :). William by the way I noticed what looks like round plastic containers you got all your whole displayed cakes in which I can see in the background. I never seen such containers what is this?
Oh and by the way what would you recommend if I want to store Pu-erh on a longer term but have a constant drastic change of humidity? Because in Winter times the humidity inside our living room is around 36-45% at best. Normally it is around 37-39% and temperature is around 23-25°. Within summer we got very high humidity maybe around 70+% with 30-40° - So summer and even early Autumn isn't the problem but what about winter? I always try to let some water boil to increase the humidity inside the apartment because we got a quite small one with all rooms open and connected. So turning on some boiling water in the kitchen increases also the humidity within the rest of the apartment - also taking a shower does its work. But in the very moment I open a window the let some fresh air in the humidity drops drastically fast. In one minute you got 54% and 4 minutes later it is already at 39% again. So it drops very fast within winter times also because of the heater.
These round plastic containers are good for showcasing tea, they can hold the cake straight up and since they are closed, fragrance is kept in the cake. Now that you mention it, i'm wondering how these cakes will age. These are more for display than drinking amyway.
Your storage situation is quite common, seasonal changes occur everywhere but on the equator. 38% humidity is very dry, according to the charts I found, your tea would be at around 6-7% and a water activity of 0.5. No microorganisms can grow under those conditions, and enzyme activity is slowed down a lot. That means your tea has a sort of dormance time, during which it won't age much. You should be able to notice a change in smell of the cakes and probably a change in taste as well.
You can weight your cakes and see if they gain or lose weight along the seasons. That will give you a more accurate picture of the actual water content, the data I give you here is theoretical and were measured on loose leaf tea.
Thank you a lot - those info really helps :) - But if the Pu is dried out a lot because of such a dry period of time during the year is it still alive? I mean I was wondering if a Pu that is already very dry can still be re-activated again. Is there a point where there is no turning back or is a seasonal change of humidity from very low to quite high always bringing the pu back to life every time again? What do you personally think about storing Pu within a non-working wine fridge using humidity packs to increase the humidity inside?
I don't see a reason why a very dry storage would kill the enzymes or the microorganisms. When very dry, they are just not working, but they are still here. However, I read on a paper about black tea that explained the volatile compounds of tea that make the flavor evaporate very fast below 5% water content, under very dry conditions it's possible to lose the natural fragrance of the tea, this is what can be observed on very dry stored pu-erh tea.
Storing in a fridge is a possibility but you should monitor regularly. If you don't have any air exchange and no temperature control, you will encounter a dangerous situation: when hot, the air inside the fridge will soak up moisture, if temperature gets lower, the relative humidity in the air will increase drastically and you'll have condensation. At that point you'll be in very humid storage conditions and despite the lower temperature, mold and bacteria growth will be very likely on the long run.
There is just one problem I got with this whole Wine cooler or clay jars storage way - A tea friend of mine for example is using the Wine cooler / fridge version with 75% Humidity packs inside. His humidity level is of course constantly around 70-75% -sofar so good BUT I noticed something about his whole Pu-erh selection he is storing inside of it - They all got a more or less similar profile to it. Of course there are some fine differences but they all got a certain flavor to them which they all share. I tasted a lot of his teas so that's why I now.
And in fact I am not wondering about it. Because they are all stored inside the same space under this certain amount on humidity they sooner or later all share a similar base note and this is something I am not very amazed about. What I really enjoy is the diversity of each and every region and specific taste but if they all gain a certain shared base profile then I have my problems with it.
And it wouldn't make any sense to air tight seal them inside such a fridge - so you need to more or less just store them only with the wrapper inside this storage unit. Ahhh.... pu-erh storage outside of Asia is really a pain.
As Xiaguan Whisky said, tea stored in the same container will share their fragrance. This is why most of the tea is stored packed by six tongs in a cardboard box, it limits airflow and also limits contact with different teas. Of course, a tea drinker storage conditions will give a different result from a professionnal storage, mainly because the scale is different. However, the good side of storing your own tea is that you will truly have a unique tea, stored in your house.
Note that the fragrance can seem to be the same if you drink directly from the storage jar, now try to break chunks of tea and store it in a small jar for a couple of weeks before drinking it, it might change and maybe show more of its original profile.
As for humidity control, you can really use the smell of your cakes as an indicator of mold growth, if the smell is pleasant, like hay, that's fine, if you start having unpleasant smells, you should lower humidity.
Enzyme activity peaks at ~40°C because of denaturation of proteins
I really like him. He´s an intelligent guy.
I just received 3 Pu Erh Cakes from him. Just smelled on the Shu / Ripe Pu Erh Cake, like an old wine.
Just go visit his Shop / Site with detailed interesting info on the different Shu and Sheng Tea Cakes.
I really enjoyed this video, thanks!
So what relative humidity do you recommend storing at? I’m setting up 3 humidors (white, Sheng, Shou) that will be roughly room temperature and blocked from any light with a very small amount of air exchange. They will have accurate humidity control (+/- 1%). I can’t decide what I should set them to?
I'd personally use 70% to get a tea halfway between wet and dry storage.
Farmer Leaf thank you! I recently found your channel, I look forward to watching more of your videos and checking out your teas :)
William thank you for the excellent videos. I'm looking forward trying the puerh cakes and samples I recently received a couple of weeks ago from your company. I live in the US Midwest in the state of Iowa. I keep my shou and sheng separated in plastic storage containers, kept slightly open for circulation in a closet. I try to keep the temperature in the 60-70F and humidity 30-40% using a humidifier.
I saw on eBay Handmade Rattan woven puerh baskets. They look very nice. What do you think of them?
Just took a closer look at the eBay site with the Rattan baskets. The dimensions seem very small. My plastic containers are 20"x14"x6" (508mmx355.6mmx152.4mm). The largest basket is 230x230x230 which is for up to 7-357g cakes. They have smaller ones too. I guess I'll stick with the plastic containers I already have.
Thank you very much for your order, I hope you will have good sessions with our teas. The storage container should not have a strong smell and allow a minimal airflow (an air-tight box that you'd open once every couple of weeks still counts as enough airflow, oxidation doesn't consume that much oxygen after all). 30-40% humidity is very low, if you have a humidifier, you should be able to reach a higher humidity. At such low humidity levels, the tea will age very slowly and might turn stale after a decade.
Does the moisture control relate to Golden Flower tea as well, since it is an aged golden fungai tea?