Monday, December 9, 2019

Alternative Uses for Marco’s Hot Box: Testing Aging Potential and Turning Young into Semi-Aged

Marco has documented rather extensively how different puerh changes in his hotbox.  He is mainly looking at the use of his hotbox as a way to optimally age puerh and even to remove some puerh qualities that are undesirable into something more optimal.  However, I would also like to introduce a two different short term uses of Marco’s hotbox…

To accelerate the aging of a less drinkable young puerh into a more drinkable semi-aged puerh.  I took a puerh that was 6 years old but still had edges on it that were a bit too harsh, astringent, cold energy, a bit hard on the digestion.  It spent a month or two in the hot box and came out with the harsh edges dropped and basically in a much more drinkable semi-aged state.  Interestingly, I put a semi-aged 8 year old puerh that was a bit harsh, bitter and hard on the stomach in the same hotbox and it didn’t really come out much less intense or aged out.  Both were dry-to-mild humid stored cakes.  I ended up putting both of these cakes into my drinking rotation rather than putting them into some long term storage.

To testing a puerh’s aging potential. I took a Lincang puerh that many had once thought wouldn’t age well because it was a very light feminine single estate gushu type puerh.  People were basically concerned that a puerh like this would loose its greatest strength which is its highnotes and lighter qualities when under longer or more aggressive aging conditions (humidity and heat).  I was considering a larger purchase and wanted to test the idea (which I strongly believed to be false from my previous experience with aging Lincang puerh). Besides I thought that this puerh had enough strength and throat feeling to hold on which are, to me, are important qualities for aging .  The consensus at the time is that the subtly would disappear and leave you with an insipid puerh.  It spent a month or two in the hot box and came out obviously changed with deeper notes revealed but still keeping many lighter nuances.

Both times I had the hot box at 40C and the humidity was pretty much pushed to the limit like a rainforest in there.  It was so humid and lots of condensation that it jammed all my gyro meters and sealed cakes had to be carefully checked and rotated every few days.  I would say that it’s using Marco’s hotbox at its extremes!  It’s a bit a walk on the wild side due to the extreme risk of mold.

The aging conditions don’t exactly mirror my actual real life potential storage parameters either but I was satisfied with the information I obtained from the experiments by pushing them at extreme conditions.  It gave me a bit more information to support my larger purchase of a certain puerh and dissuaded me from a larger purchase of another.

I hope to review these puerh in the coming months with some side notes on how they changed.



marco said...

Wow Matt you are pushing it to the limit! I have one hotbox at a higher temp i.e. 40C but still with humidity in the 60s. How do you manage the condensation, you let it get a bit wet and then dry it out in phases? You are trying to do HK Trad in a hotbox.

Teaboy said...

HI matt!
Just to be clear, the cakes are sealed but outside of that there is very high humidity? How come? Why not keep it at natural humidity since the cakes are sealed anyway? Just curious.
I'm always excited about people trying to aggressively age puerh.

Anonymous said...

how does it give you an indication about aging if it is a completely different storage than yours?

If I remember correctly Shah once wrote that different regions react well to different storage types.. That Jinggu (XZH) aged well in humid places, in contrast to another area (can't recall..)

Matt said...

Marco & Teaboy,

It is apparent to me through these comments that I was a bit vague on the details so let me try here to be as specific as I can....

I took Marco's hot box design as linked in the main article got the temp to try to climb as close to 40C as possible. Then I added in about 5 squares of tap water dampened paper towel to the point that water was not leaking out but that it was pretty much fully saturated. Then I placed this paper towel in the hot box.

I had wrapped my cakes when then arrived by mail in Saran Wrap which is a clear cling food wrapping then placed them in a Ziploc bag (I now recommend Mylar as it seals better- another Tip from marco). I took these cakes out of Ziploc but kept them wrapped and placed them in the hot box.

When the paper towel would dry out I would just add another. It doesn't take long before condensation fills the hot box. I would wipe away the condensation with a dry paper towel even daily to a few days. After a while you can see the wrapped cakes start to fog. When this happened I would closely monitor and rewrap them in saran if needed.

The point was to keep the condensation going only in a mild state and have the wrapped cakes have a very mild to not much fog without getting the wrapper wet. It is maddeningly hard to do. The conditions, as I said are rainforest like.


Matt said...


Yes, it’s kind of done in phases so as to remove too much condensation while still keeping it going. Truth is that Hong Kong Traditional storage is one I have very little experience with. How about “unconventional Hotbox storage”? Hahaha


Matt said...


These are good questions...

If aging is considered in this way:

Then adding aggressive amounts of heat and humidity could, theoretically, bring a puerh into an aged state. Even though it doesn’t represent the aging that I intend for the puerh, it could show us that the puerh can come out decent on the other end of aggressive storage. If it comes out good after aggressive storage than I think it’s safe to assume that it will also do well in less aggressive storage.

I totally agree with the statement that different regions, how tight the puerh is pressed, how it was previously stored, other characteristics of the puerh itself dictate an optimal storage direction for each puerh production. It also depends on what characteristics in a puerh the person aging it is looking to accentuate or which characteristics they prefer with aging and each persons limitations with aging.

I think as a general rule certain regions preform better in certain storage, but as stated above, it’s personal and there are many other factors. I just tired a Kunming dry stored 2002 thought to be Jinggu and it’s dry storage was brilliant. Even Shah likes this one dry.

Interestingly, the two cakes I tried to age one was bulang/ Menghai which I thought would aged better and drop the harshness and it didn’t. The other was lincang which I thought would suffer more and it came out on top. I think if I did this for a few monte months/ years the bulang would have benifited.

Both cakes were from the same warehouse but I did check the cakes humidity before putting them through the experiment.


Anonymous said...

At latitude twenty four(sub tropics) it takes a year and half to get an idea of the long term ageing potential of a tea. The storage is year around windows open by the sea.

Matt said...


Sounds glorious. For you the issue is more about slowing the aging down.