Black Tea Storage Experiment: Unheated vs 36C (6 month results)

The purpose of this experiment is to observe the effects of heated storage on the aging process of sun-dried black tea.

For this experiment, I chose 2018 Natural Redhead from white2tea. It’s sun-dried and in cake form, which indicates that it should improve with age (as the store page confirms).


  • The cake was conditioned to ~50% RH using a Boveda pack, then split into two halves.

Storage Treatments

  • A – 22C, 50% RH, sealed in mylar
  • B – 36C, 50% RH, sealed in mylar (Boveda not included)


  • A – Just as I remember this tea from 6 months ago.
  • B – I noticed a strange sharpness in the back of my mouth during the first cup, which subsided and did not return in subsequent brews. I noticed an aroma and taste in this tea that is identical to what I get from the 90s aged dianhong from Teas We Like. The overall profile of this sample has shifted in that direction. It tastes not just warmer, but “hot” in a way. This sample was a little less sweet, and a little more sour than the unheated one. It’s difficult to describe the overall taste without simply pointing the reader at that dianhong, as I don’t have much experience with aged black tea.

I’m not yet polarized toward one storage method or another. Expect an update at the 1 year mark.


  1. Have you done an experiments or have any intuition about higher RH% levels for aging black tea?

    I am doing an experiment now with dry, 65%, and 72% for a variety of black teas, but I have a long way to go before it will be ready to evaluate.


    1. I don’t have much experience aging black tea, or even drinking aged black tea. One reference I can point you towards is the 2016 A&P from white2tea. That tea has seen a good amount of warm, humid Guangzhou storage by this point, and the last time I tried it, it had a thick chocolatey taste that I haven’t found in any dry-stored black tea. If your storage goals are on the humid end for black tea, it’s worth trying the A&P to get some idea of where your tea might be headed.

      Re: The 65% vs 72% RH black tea experiment, if your ambient temperatures are anything like mine, meaning usually around 21-24 degrees Celsius, it’s going to be a relatively long time until you can even tell a difference between the two samples. Until then, the main difference would just be a matter of conditioning, meaning a simple difference of moisture content in the leaves rather than actual development over time as a result of microbial activity.

      I have already set up experiments to tackle this, but for your own experiment I recommend keeping the 65% and 72% Boveda packs inside the bag with each sample of tea, and putting those bags in heated storage, around 32-36C. It could be more risky, so don’t try this unless you’re okay with ruining the tea. The higher temperature means that the samples will absorb much more moisture from the Boveda packs, progressing faster. At least for my ambient temps, between 65% and 72% RH, there’s a pretty negligible difference in absolute humidity, which I hypothesize to have a significant impact in practice, more so than RH. I recommend plugging some numbers into this calculator to get an idea of what I mean:


Leave a Reply

Your email address will not be published. Required fields are marked *