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Tuesday, March 1, 2011

How to store your puerh tea

I was so excited! One of my friends invited me to taste a puerh tea produced in the 1980s. The cake had just arrived from China, and in a week we would meet to share it together. This week seemed neverending. When the date we set finally arrived, I raced to his place for a taste of something genuinely special.

After eagerly opening the paper wrapper, I noticed some white spots spread unevenly over the surface of the tea. This elicited my first concern about its quality. Raising the cake for better inspection, my excitement was stifled by the odor of mold. This stink was immediate and conclusive proof that the tea had been tainted due to poor storage. I didn't want to disappoint my friend so quickly and kept my silence as I carefully separated the cake and prepared the tea. The liquor was dull and dark like ink. The flavor was muddy and moldy. It all confirmed my original suspicion that the tea had been contaminated.

How did this happen? The tea was stored in an overly warm and moist environment, either due to negligence or perhaps to hasten fermentation. As a result, the amount of moisture the tea absorbed rose over 10% of its total mass, creating felicitous conditions for growing mold. In China, it is not unusual to use warmth and moisture to mature puerh while it is in storage, although they are supposed to be controlled. We even have a professional term for this: "wet-stored" (shicang 湿仓) puerh. As one might suspect, the alternative is known as "dry-stored" (gancang 干仓) puerh.

Of course, it is both very disappointing and frustrating to age a cake for decades, only to grow mold, or produce what should have been a delicacy and is now only compost. So what are the significant points we should know to store our tea properly?

1. Air Circulation is necessary 

Don't store puerh in a plastic bag or airtight container, because the microbes that cause fermentation need to breathe. Constant and regular air circulation will help the tea develop and blow away odors. However, puerh should not be kept anywhere breezy (e.g. next to a window, doorway, or on a balcony), as the wind will carry its aroma and flavor away. In sum, moderate air flow is important, but drafts should be avoided.

2. Constant Temperature is necessary

The best temperature to store puerh is between 68-86°F (20-30° C). If the temperature is too high, it will affect the mouthfeel. The taste could become dull, flat or sour. In addition, raw (sheng 生) puerh will sometimes develop into cooked (shu 熟) puerh (this has been reported for tea stored in Hong Kong). This means a normal indoor temperature for us would be suitable for puerh as well.

3. Moderate Humidity is necessary 

As mentioned above, puerh is divided into two kinds according to storage method: "dry-stored" puerh (gancang puerh 干仓普洱) and "wet-stored" puerh (shicang puerh 湿仓普洱). The former refers to tea allowed to ferment naturally in an environment that is relatively dry, ventilated, and moderately hot; the latter refers to tea aged in an environment with low ventilation and high humidity in order to hasten development. This is done sometimes because the tea producer can make more profit on it. 

                                                                    "Dry stored" puerh

                                                                  "Wet-stored" puerh

If the environment is too dry, it will slow down the ageing process. So if conditions where you live and keep your tea are dry (e.g. maybe you live in a desert or alpine environment), you can put a glass of water next to your puerh, to increase the nearby humidity slightly. Alternately, if conditions are too humid, it will typically result in mold, as happened to the tea I tried at my friend's house.

4. Avoid any odor 

Tea is very good at absorbing any kind of odor. Not long ago, I bought a second-hand dress that had a strong unpleasant smell. I didn't want the stench to spread to the rest of my clothes, so I left some loose tea leaves in the dresser drawer. A few days later, the tea had the strong smell of the dress, which itself smelled better than before. My advice is that you should never store your tea, no matter what kind, in an environment that has any other scents whatsoever.

5. Material to wrap the tea

Imagine tea has a life like us and needs to breathe. Pack your tea in something made from a permeable material, such as organic nonwoven bags, kraft paper bags, paper towels, wooden or cardboard boxes, bamboo baskets or husks, clay or porcelain containers, and so on. I strongly recommend you do not put puerh tea in a plastic bag if you are planning to store your tea for years. Moreover, do not keep tea in a metal container. Remember that whatever packaging you choose should have no other smell.

Once you understand puerh as having a life just like us, it becomes easier to see how to keep it alive. It should have a comfortable place to stay; somewhere not too fancy or complicated. There is no need for refrigeration (remember I am talking about puerh, not green tea), no need to seal it in an airtight container, no special equipment and no direct sunlight. You can store it in your study room where there are no other smells and some air moves through. If the room is too dry or humid, it is better to open the window once in a while. In Pacific Northwest weather or during a monsoon, the tea has a greater chance of growing moldy, so remember to examine it occasionally. Finally, I want to remind you yet again that you should never keep your tea in an area with other smells, such as a bathroom, kitchen, new cabinet, drawer holding soap, incense, etc. Moreover, you should understand that puerh cakes from the same production line will have different aromas and tastes because they have been aged in different conditions. Decades after they are made, one from Yunnan will never be the same as one from Hong Kong, Taiwan or the USA.

One final aside is that you should not store cooked and raw puerh together.

I am sure if you follow these rules to store your puerh tea, the tea will be safe and develop well. Enjoy it, and don't forget to invite me by for a sip! :)


  1. Certainly it sounds the tea has been contaminated. I am not quite sure about the temperature as you have mentioned in the article. It is better to let the raw Pu-erh to ferment slowly and naturally. A proper enviornment where you store is very important, make sure it is not tainted.
    Humidity is critical for the storage of Aged Pu-Erh. Basically it should avoid sun light, better in cool shadow with good ventilation.
    When the cake is being seperated, suggest to keep it in a ceramic tea jar (i.e. Yixing clay jar) and let it rest for about 1/2 month.
    Can also consider to roast the aged pu-erh a little bit before you make tea from it.
    The sour taste that you have mentioned, is it very mild sourness or very vivid sourness? If it's very mild sour taste, it could be meant the tea is still in the fermentation process; but if it is very vivid sour taste, then I wonder if it's healthy drink such sour tea.

  2. just another tea drinkerMarch 30, 2011 at 4:06 PM

    Hey Becky

    Your comments on the "wet storage" of puerh are a good reminder that sometimes it simply isn't possible to take shortcuts. Certain activities require a minimum commitment, no matter how one might try to get around it.

    It also provides a good example of the principle of "unintended consequences", in that the goal of the producers who kept their tea in "wet storage" was to improve it without having to go through the slow process involved, and the result was to ruin the tea completely (although you made it sound as though it could be done successfully if done very carefully - is this correct?).

    Similarly, when one wants to build an online reputation, it typically requires time to provide a consistent picture of oneself to others for their judgment. Trying to skip this by posting all over the place with comments that don't add in a helpful way to the discussions at hand might well quickly build a reputation, but one quite different from to what was intended.

    However, in both cases, the product (whether tea or text) does provide others with an accurate sample of the standards and motivations of its creator.

    It seems to me that this shows we can't hide ourselves, no matter how hard we try - we are exposed by our actions - so we might as well try to do our best. For example, I'm a generally cranky guy, so I make cranky comments on others' blogs. Here's one: Chan/zen is a living tradition with a lineage, and anyone outside it who presumes to make pronouncements about it is just speaking of an idea. Again, we expose ourselves through our actions. Ultimately, we can only tell what we know - our ignorance speaks for itself. (Anyone who bothered to read that and now wonders where the heck it came from should look at the name of the first commenter above.)

    On this blog, your knowledge and love of tea show through in every post, and I'm glad to have the opportunity to read them. My only complaint is that you should post more often. I've been waiting for another entry, but it's been so long I decided to comment on this one. Please ma'am, may we have some more?

    Thanks in advance

    - some cranky guy obviously in need of another cup of tea

  3. Since two people have taken the time to comment on this entry, I guess I really should say something….

    I must confess, I'm not sure I understand the concern in the first comment about the temperature I recommend for storage - especially when it then repeats my advice. I mean, I can't really disagree with what I myself said, but I don't see how this raises doubts about the temperature range I mentioned.

    In fact, what temperature is appropriate for storing puerh is a technical question, that has to do with providing an environment suitable for the community of microorganisms that help puerh ferment (notably fungi like Aspergillus niger, but also yeasts such as Blastobotrys adeninivorans and bacteria from the family Paenibacillaceae, among others - there are lots we haven't identified yet, and they all have really big names - so in appreciation for the great taste they help develop, you can practice saying them while you drink your tea... on second thought, don't do that). Of course, we also want to prevent the growth of dangerous organisms - it's similar to wine or cheese, where growing some "bugs" helps prevent others, and the trick is helping the beneficial ones to thrive.

    Sourness in tea - as with any food - is a matter of acid (citric, malic, tartaric, etc. - but not amino acids, which generally taste sweet or umami). Unprocessed tea leaves have a certain amount of acid (e.g. quinic acid, which actually decreases during processing); however, most of the sour taste in properly made puerh comes from gallic acid + some other compounds that develop with fermentation.

    About sourness: What I tasted was an unpleasant sensation that remained in my mouth for a long time, and resulted from compounds that developed due to improper storage or possibly other mistakes in production. I agree with the first comment that this sourness indicates something unhealthy. No surprise there, I suppose.

    However, this issue makes me think of the famous sour tea (suan cha 酸茶) produced by the Deang (德昂族) and Bulang (布朗族) ethnic groups in China, which is said to be particularly good for digestion. In fact, many sour foods are famous for their health benefits - so, sourness in itself isn't necessarily bad - even in tea. It all depends on what kind of sourness it is.

    Finally, to the second comment by the tea drinker: You are right, some "wet stored" puerh is sold openly. However, many sellers try to use this technique to fake aged teacakes, so be careful! I don't like the taste anyway, so it's something I simply avoid.

    Thanks for the comments, and I'll try to write more soon. But not now. Right now, I want to sit down, relax and enjoy some aged puerh - this is tea I tried already, so there shouldn't be any unpleasant surprises. Ha!


  4. Hi Becky!

    I just wanted to say thank you for this post! My husband and I visited you at Vital T-Leaf 10 days ago and had an amazing experience we are still talking about. I'm just putting away the puerh and tea cups we bought and will use the pointers you list above for long term storage. You are an excellent teacher!!!


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  6. did you still drink the moldy tea??? why didn't you tell your friend?

  7. Great post. Thank you very very much.This article is efficient. Thank you for sharing it with us.
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About Me

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Seattle, WA, United States
I grew up with tea, and it continues to fill my life with so much beauty and discovery, pleasure, peace and friends. It is always leading me toward a greater understanding of culture, nature, myself and others. It is my hope to use this space to share the joy of tea and tea culture with you.