Young Raw Puer Storage Experiment: The Role of Oxygen

The purpose of this experiment is to demonstrate the role of oxygen in imminent drinkability of young raw puer.

For this experiment, I used a 2018 Jinggu raw puer from Yunnan Sourcing.


  • Boveda packs were used to condition the cake.
  • The cake core was removed prior to reduce sample variation.

Storage Treatments

A – 22°C, 65% RH, sealed in mylar

B – 22°C, 65% RH, sealed in mylar with oxygen absorbers

C – 22°C, 65% RH, vacuum-sealed

D – 22°C, 65% RH, vacuum-sealed with oxygen absorbers

Evaluation (90 days)

Visually, I noticed that the samples stored with oxygen absorbers decompressed quite a bit. The leaves were also much more flexible and resistant to breakage.

A – Pungent, zesty, sweet, complex. Explosive aroma. I could go on.

B – Easily the worst. Very plain in taste, in a strange way.

C – Better than either of the samples stored with absorbers. More of a proper natural taste, though terribly repressed in comparison to A.

D – Comparable to B, but not nearly as poor.


Somehow, removing oxygen caused the tea to decompress, and the sample in the vacuum sealed bag decompressed less than the one in mylar since it didn’t have enough room. Notice the correlation: the more decompression, the worse the tea. However, it’s possible that the higher air-permeability of the vacuum bag had something to do with the fact that it performed better than the mylar stored sample.

After tasting the samples a couple of times, I tossed out all of the oxygen absorbers and stored all the samples at room temperature in a mini pumidor (very little airflow) with 65% RH Bovedas.

Evaluation (180 days)

A – Good bitterness followed by huigan. Sweetness, pungency, complex sheng notes. Great condition.

B – Dry leaves are still quite flexible, though not as much as before. Rinse aroma is dead compared to sample A. It has less sweetness, and is not very flavorful or complex. Huigan is absent; the tea lays flat in the mouth. Little in the way of mouth or throat sensations after the swallow. I would not drink this in its current state, for which I have no solution other than waiting. That said, it tastes better now than it did at the 90 day mark.

C – Similar to A, just more “dense”. Not as enjoyable as A, but not problematic either. Good condition, much better than it was at the 90 day mark.

D – Similar to B, but not quite as poor.

Once again, A>C>D>B.

It seems to me that oxygen needs to be present in the storage environment for optimal drinkability of young raw puer. No statements are being made on optimal aging conditions.


  1. This is interesting. I recently experimented with putting my cakes in gallon-sized plastic bags with 65% Boveda packs, 2-3 whole cakes per bag. They stayed in a consistent room temperature. After just a few months, nearly all of my cakes lost their flavor – completely insipid. My thinking was that an environment that retained humidity in what is otherwise dry storage conditions would result in better flavor. Completely opposite result.

    I’m now in the process of trying to bring them back to life, but needless to say, I have completely scrapped the plastic bag storage and now have them all in a larger bin with Boveda packs. Interesting how your mylar storage (which seems comparable to what I had) yielded the best results.


    1. Hi Jeff, as luck would have it, I know exactly what happened to your teas, because I made the same mistake myself recently. I stored about 4 tongs’ worth of aged raw puer in Ziploc freezer bags, and placed them on a shelf for a few weeks. I was in the process of building a heated storage cabinet and had left the doors off their hinges since I was still lining the interior with thermal insulation. When I came back to those teas, I found that every single cake had lost most of its storage taste, despite not having dried out! I assumed that the teas had been damaged by my ambient indoor lighting (no sunlight), but that was not the case.
      The issue is that plastic bags are too permeable. Mylar is much less permeable and will keep your tea flavorful. I would move all of your tea into mylar or some similarly semi-airtight, low-porosity container and give it a few months. My teas haven’t recovered fully yet, but they are on a good trajectory.


      1. Thanks for the reply. The baffling part for me is that my original storage was just a big plastic bin with Boveda packs – this at least had maintained the original flavors of my cakes over several years. However, after not noticing an improvement in their aging or flavor, I decided to move to the freezer bags in the hopes of jump-starting a little more aging.

        The freezer bags full of puerh were then put back in that same container. I understand the permeability of the bags being a suspect in the teas losing their flavor, but ultimately they were no worse off than when I stored them without bags in the bin.

        I had originally thought close contact with Boveda packs was the culprit, but internet cigar afficionados claim no effect on their cigars when in contact with Boveda packs.

        My second thought was that the cakes didn’t have enough airflow, but that is not maintained by your experiments, especially given that the permeability of the bags resulted in your cakes’ loss of flavor.

        Anyway, I’m baffled. Certainly going to try the mylar storage route and see what happens. Thanks again!


        1. Interesting. I can confirm, I haven’t had any issues with Bovedas. I think it’s possible that those plastic bags absorbed the flavor from your tea, even if it was all contained in the enclosure. I will say, that is a surprising result. At this point I haven’t heard anything good at all about plastic bag storage and will have to phase them out completely.


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