listening to leaves: October 2012

It begins, March 2012.. plywood purchased and cut

It all started like many of my wild ideas -- reading through blogs, forums and articles. Then it continued and blossomed in email correspondence and phone calls. Makes sense, doesn't it? You only need to taste the difference between a dry stored tea and a "traditionally" stored tea ("wet-stored," for those who don't keep up with MarshalN's musings) to know that the environment a tea is stored in will have significant effect on the taste and aroma. But here in the West it's all still quite new (pu'erh collecting, that is). While there's an abundance of opinion (experienced and otherwise), plus a few brave souls who are actually trying a stab at something other than just sticking their beengs in an empty shelf, it's still definitely in the experimental stages. No one really knows for sure.

Angled screw holes, ready for joining

But I was curious. When asking around I got a lot of responses to the effect of "Well, you live in the Pacific Northwest! You've got PLENTY of humidity! No need to worry!" Sure, maybe if I stored my teas in an unheated yurt in the backyard I wouldn't have to worry about humidity. Except that I live in a very comfortable house with central heating and A/C, and this is where my teas live, too. Even so, not being one to cling to "One Truth" in any guise I decided to find out for myself. I purchased a couple of hygrometers, set one inside the house and one outside and spent a week checking on them throughout the day/night. Sure enough, the indoor humidity levels stayed quite low in the mid-50% range, while the outdoor levels moved each day from the mid-60% range up to 80% plus (this was back in January/February of this year). Once it was established that just because I live in a notoriously rainy climate doesn't mean that my teas are benefiting from all that humidity, I decided to continue with the experiments.

We made 8 of these in total, about 4x4 feet square (just one corner showing here)

Somewhere I landed on a couple of descriptions of someone (Tim?) using a temporary method to boost the flavor and aroma of his teas. Temporary is key here, because this method involves storing the teas in air-tight plastic bins for a short time (a month or two, although I had mine in there for about four) along with some sort of humidifying agent. If you do any reading on the storage of teas (or cigars) you quickly learn the importance of some minimal amount of air flow, otherwise you're just begging for mold growth and the ruin of a lot of good tea. I decided to keep it simple and safe and purchased a bunch of Boveda 72% RH packets to toss into the bins. I also placed a hygrometer into each bin to keep an eye on what was happening. Interestingly, it took several weeks (and several more Boveda packets per bin than I'd planned) to get the RH up to 70%. Clearly, my teas were very dry to begin with and it took some time for them to absorb the moisture.

Gluing two 4x4 frames together, extra support for the back wall of the cabinet

But good tea storage isn't just about humidity levels. Temperature also plays an important role. Somewhere out there in the online tea world is an excellent blog post and forum discussion or two (written in large part by the Zhi Zheng tea guy, who's knowledge I've relied upon to great degree), all about humidity, temperature and that thing called the dew point, which involves some pretty fancy math but is basically a calculation of humidity and temperature (I'm not going to get all technical on you here, you're welcome to google away a few hours to learn more). For my little tea storage experiment here at home I'm fortunate to have a small room in our house that stays a whole lot warmer than the rest of the house (brilliant central heating design, at least for my teas), maintaining a temperature in the low 70's at night and in the upper 70's to low 80's during the day. From what I've read, this is the lower end of what might be considered ideal temperatures for storing tea, but it's still in the ballpark, so at this point I'm not artificially boosting temperatures.

Routering out the grooves for the cross-braces (will make more sense in next photo)

Okay. Back to my story. So I put all (or most -- I kept some duplicate cakes out for comparison purposes) of my teas into these air-tight bins along with several Boveda 72% packets. Then I waited a few weeks for the hygrometers to even reach the 70% goal. Then I let them sit like that and would frequently open the bins to smell and taste the teas. After a good month of maintaining 70% humidity and 70+ degree temperatures, something happened. The aroma of the teas was incredible! Really blew me away, they smelled SO GOOD. Taste-wise things were getting impressive too, although the change in taste was not as pronounced as the change in aroma. At this point my guess is that aroma is more sensitive and quicker to respond to storage conditions, while depth of flavor is something that requires longer exposure to optimal storage conditions. But this bursting of incredible aroma from the teas was enough to convince me that storage with increased humidity and temperature (relative to sticking my teas in shelves in the dining room) was worth pursuing. And so began the big "Tea Pumidor Project."

Big picture view, all 8 4x4' frames have been clamped tightly together while being routered

(a side note -- While the teas were in the air-tight bins I kept very careful watch of them. All did fine for the four months they were in there, but one brick did start to develop a few little spots of white mold, this 2005 Dehong brick, which I removed from the bins and which is still sitting on a shelf in my very dry dining room)

First, the design. I've got a lot of tea, far more than I'll ever consume in a single lifetime no doubt (common scourge of tea lovers, I hear), so the cabinet dimensions needed to be big. Roughly, it's about 4 feet high, 4 feet wide and 2 feet deep. Another factor in determining the dimensions was the available space in the small overheated room where the cabinet would be placed. Next, we (my husband and I) needed to figure out how to construct the thing. Thus began my evening hobby of reading cigar blogs and forums and making friends with cigar folks discussing the important considerations when constructing cigar humidors. So many options! Should I use an already-constructed cabinet and retrofit it? Should I buy an enormous cooler (like some enterprising DIY cigar aficionados do) for the great insulating capabilities and add a good humidifier/fan unit? Maybe find an old non-working refrigerator, add some humidity and an incandescent light bulb and call it good? I could fill numerous blog posts about all the many options I pondered, but considering this one's going to be a doozey as it is, I'll just stick to what I decided upon and do my best to explain why.

Wood frame portion nearing completion

In short, the outer shell of the cabinet is constructed from plywood, the inner walls of the cabinet (which are also sealed so there's no intermingling of potential plywood chemical-glue sketchiness with the teas) are lined with food-grade HDPE (high-density polyethylene), and sandwiched between the outer plywood and inner HDPE is an inch and a half of rigid foam insulation board. The shelves are a coated wire shelving to allow for good air circulation, and the whole thing is humidified by one of these fantastic units from Aristocrat Humidors (Bob Staebell is excellent to work with, extremely knowledgeable and helpful).

I can hear the cries as I write this -- "HDPE plastic?!? wtf??" Well, I'll tell you. Keep in mind this is all one big experiment, and this is simply what seemed to me the best possible solution to the matter of potential infiltration of non-tea odors into the teas, thus altering the classic puerh taste and aromas. If I change my mind on this (and I may.. we'll see), I'll let you know. Cigar humidors are traditionally lined with Spanish cedar which is an aromatic wood that imparts a desirable light woody flavor to the cigars as well as keeping bugs away. But I don't want my teas to be infused with cedar aromas, no matter how much I like the smell of cedar. Some will argue that there are other wood species available which do not have a strong woody aroma. While it's true that some woods are less aromatic than others, my feeling is that all wood has some degree of smell to it. Put that wood into a warm, moist environment and even the least aromatic of woods is going to give off a certain aroma. The advantage of HDPE food-grade plastic is that it has no detectable aroma. None. Zip. Zilch. It's also extremely dense, slick and ultimately non-porous, which means that nothing sticks to it -- not mold, not mildew, not even any glue or sealant known to mankind (more on this challenging bit below).

ahhh, there is it! Ready for insulation and HDPE

For those of you thinking about building your own pumidor, there are options other than wood or HDPE. I've considered at least one of these, and may very well build another cabinet to experiment and try it out. One possible lining is a skim coat of light cement or lime plaster (for all of these options, I'm talking about the old-school simple-ingredients DIY mixes, not the chemical-laden modern "just add water" versions). I even thought of brick and mortar, such as purchasing large natural terra cotta floor tiles to line the walls with, or even making my own tiles with a natural clay (and put that kiln of mine to good use!). But the clear disadvantage to these is weight, and since I hope to actually be able to move this cabinet around if I need to, I ruled these out (for now) even though they strike me as potentially good options with regard to issues of insulation, humidity control and/or potential odors.

Working with the HDPE was tricky. Like I mentioned above, NOTHING sticks to this stuff, so while it would have been super easy to just glue it down to the insulated wood frame (Plan A), we had to improvise (Plan B). You can see in the photos that the plastic is secured by metal screws. Specifically, stainless steel screws with a dab of aquarium-grade silicone sealant in each screw hole. I said that nothing would stick to HDPE, and while that's true, it's also true that stuff (like silicone sealant) will stick to it AS LONG AS the piece stays perfectly still. If you put silicone between two sheets of HDPE, let it dry and then moved the two pieces of HDPE even just a little bit, the sealant would pop right off, but it sticks as long as there's no movement. Hopefully, given the stability of the cabinet (believe me, it's a monster of stability) and the fact that I don't plan to move it once it's in place (barring any unforeseen circumstances), I think the silicone will hold for the purpose we need it for -- to seal the inner chamber holding the teas.

Rigid insulation cut and ready to install

Sealing the inner corner seams of the cabinet was another hurdle. To save some cost, we had purchased a very thin HDPE sheeting (1/8") for the inner walls, and given that we hadn't anticipated the difficulties of working with this stuff, we didn't have a lot of exposed wood to screw it to from the inside. The seams along the corners were particularly problematic because the plastic would warp and buckle despite our best efforts at virtually carving each piece to fit as perfectly as possible. To solve this we placed aluminum angle iron (or "angle stock" because it's aluminum, not iron, right?) along the length of each inside corner, as well as along the perimeter of the opening where the doors will (someday) be placed, screwing it to the wood where ever possible and sandwiching a bead of silicone sealant between the aluminum and the plastic. This addition of the aluminum actually turned out to be a big positive when it came time to put the shelves in. The aluminum provided some very sturdy, and much needed, extra support.

Insulation along back wall in place

For this project, my biggest worry was about the potential for unwanted aromas infiltrating my teas, so once the cabinet was built and ready to be filled, I waited to put the teas in. I needed to know for sure there were no odors. I put the humidifer unit inside (no teas), closed the "door" (more on this door matter below), let it come up to the desired temp/RH levels, then I opened it and gave it a big whiff. It stunk to high heaven! I was dismayed but knew there had to be a cause. But what was it? The smell was a sour chemical one, more sour than chemical. There were only two possibilities -- either the brand new humidifier unit was off-gassing, or the silicone sealant was. My guess is the sealant. I've smelled a similar scent when using silicone sealant in remodeling jobs. So, I waited. And waited. And waited. In all, it took about 8 weeks for the smell to disappear completely. During that time I would alternate between closing up the cabinet and letting the humidifier run, and opening the cabinet to let it air out with no added humidity.

Placing insulation in side walls

Finally the day came to put the teas in! I'm very happy to report that the cabinet was built big enough to hold all my collection with a bit of room to boot (although I think I heard my pocketbook audibly groan with the news). Thanks to the 2-foot depth of the shelves I can line the stacks of cakes two rows deep (something I probably won't do again if we build another one, to make it easier to find teas). It's important with these humidity units that you allow a sort of "chimney" above the units, not placing any tea directly above them. Otherwise, those cakes would impede the flow of the humidified air and become too wet.

A note about circulation. This is one of the beauties of this particular humidifier unit. When the unit turns itself on to maintain the humidity level (which you pre-set to whatever you'd like on the main contol) a little fan atop of each unit turns on to direct the flow of air upward (why you don't want to place any tea directly above the units). Then, along the top back corner of the cabinet two additional fans (a bit smaller than the ones on the humidifier units) turn on at the same time (as well as intermittently at other times) to direct the air flow along the top of the cabinet and down the front, in a big circulatory effect. The fans don't operate constantly. They turn on only when the humidifier units turn on, and then intermittently between. The flow of air is very slight, but still discernible if you stick your hand inside the cabinet while they're running.

Screwing down the back wall of HDPE

Finally, the door. As you can see, there is no real door. This is not because we planned it this way. It's because building doors (especially doors that are perfectly square, with the ability to seal completely) is a challenge for folks like us who don't build cabinets for a living. The doors are a work in progress. But because this project has been so long in the making (started in March), and because I had taken the teas out of the air tight bins and was getting nervous as each day passed and I knew they were drying out again, I wanted to get them in there. So we improvised a door, for now (Plan C). It's a large piece of extra-thick plastic sheeting (and not the HDPE kind, just the kind you get at the hardware store... not ideal, but working for now) which is held to the cabinet thanks to a perimeter of velcro. Totally low-tech. So it goes.

Cutting and placing side walls

Oh yes, one more thing. I'm disabling the comments for this post. I know this whole puerh storage thing is a hot topic, and there are plenty of places to discuss (and argue) it. I just don't want my blog to be one of them :) If you have further questions about how we went about building this thing, or if you've built your own pumidor and want to swap notes, please do send me an email (openingone-at-gmail-dot-you-know-what-comes-next). Remember, this is all just one big experiment. Although I read everything I could find on the topic and then some, I don't know how this will all ultimately work out. Just like with the air-tight bins, I'll be watching my teas like a hawk, checking frequently for any signs of "Turn back! Re-think!" (we're talking mold, strange tastes or odors, stuff like that). Also keep in mind that we're not professional cabinet makers. Not even close. I'm sure if there are woodworkers out there reading this (or even just looking at the photos), they're either cringing like they just bit into the sourest apple ever, or laughing uncontrollably on the floor. And lastly, I promise to keep this blog updated with any new developments or learnings about this whole thing :)

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