; Cwyn's Death By Tea: What a Puerh Lover Learns from a Fruitcake ;

Tuesday, December 19, 2017

What a Puerh Lover Learns from a Fruitcake

This year I decided to bake a fruitcake. I have made fruitcakes before, and even have a recipe I developed back in my vegan days using beans. For this year’s fruitcake, however, I wanted to make a rather boozy version along the lines of a fruitcake I picked up during a trip to the UK a few years ago, what was called a “Christmas cake” with frosting. This cake tasted very unlike the fruitcakes I avoid here in the States. 

Many Americans dislike fruitcakes, mainly because of mass production of this confection in the mid-twentieth century with nuclear green candied fruit. I learned from my English fruitcake that many US mass produced versions are mistakes, but what I did not know until this year is that a quality fruitcake "matures" in a rather similar fashion to our puerh cakes. That is, if looked after properly, a fruitcake and puerh over time will develop sought-after complex flavors.

For my fruitcake, I hoped to use up much of the dried fruit accumulated in my kitchen cupboards over many years. Alas, one large fruitcake made only a small dent in the number of packages of prunes, apricots, dried cranberries, figs and the like that somehow ended up in my house. Where did all this dried fruit come from? I like dried fruit, but really! Apparently I do not eat any of it, and neither does anyone else in the house. I guess I ate it to stay regular, but now in recent years I need only brew up a drain cleaner puerh for this purpose. 

Fruitcakes are part of my family history. My aunt Alvina baked fruitcakes every year. She developed a family tradition during World War II when my uncle Leonard fought as an infantry soldier. Aunt Alvina sent him care packages at Christmas time with fruitcakes and frosted cookies packed into a huge box full of plain popped popcorn. The box arrived with most of the cookies broken, but the popcorn and broken cookies eaten together were a huge hit with my uncle’s infantry unit. So Alvina continued mailing out Christmas boxes to her brothers, my father included. Dad was the only one in my family who ate the fruitcakes. They remained in the refrigerator wrapped in tin foil well into the following summer (I found out the tin foil actually has a rationale for maturing fruitcakes). 

I remember asking my dad one July whether I should toss the leftover fruitcake.

“No, no don’t throw that out, it is still good.” 

He’d hack off a chunk, eating it in front of me to show he still planned to finish the cake. One could never be certain of food facts from my father. This was a guy who ate lettuce and pasta out of the sink drain, and saved soups in pots out in the garage for weeks.  

So really, in terms of fruitcake knowledge, I am on my own here. Although I have plenty of fruitcake recipes in my kitchen already, I am intrigued by a BBC recipe. Sort of following the recipe, I cook up prunes, apricots, cranberries and figs into spiced rum (I am not a brandy fan) and then fold them into the cake portion of the recipe. I did not have fresh lemons, so I use a chopped preserved lemon. I cannot bother to go buy one orange just for the zest, so I toss in some fruit punch instead. I slow bake the lot in the oven and the cake turns out all right.

My fruitcake
Now, this is when the OCD kicks in. I have some notion that a fruitcake needs to mature with some alcohol in it, but not much idea of how to do this because all the fruitcakes of my past were ready to eat. How much booze do I use? How often should I add some to the cake? Do I just pour it on, or brush it on? How long should the cake sit, weeks or months? I turn to the internet for information.

Let me tell you that every single fruitcake article on the internet for the past seven years is repetitive and blatantly plagiarized from the same sources without attribution. I am ashamed at all the blog posts I read on fruitcakes that repeat the same tropes over and over as if they are original to the author. A typical fruitcake article has the following:

--a trope on ancient Roman fruitcakes
--a trope on Filipino fruitcakes
--a Johnny Carson joke
--a Jay Leno joke
--a trope on American fruitcake nuclear green tutti frutti (even I repeat that one here)
--the American designated day for fruitcake toss games.
--the 106 year old fruitcake found in Antarctica, still edible.

Finding useful and apparently obscure information on “maturing” fruitcakes takes no fewer than eight pages into a Google Search, and I ended up scouring more than twenty search pages.

So, a fruitcake “matures” over time with periodic “feedings” of booze. The skins of the fruits break down, releasing the tannins. The flavors of the tannins reduce the sugary sweetness, balancing it out and creating flavor nuances. In this sense, fruitcakes are more akin to wine maturation than puerh fermentation.

97 year old Australian fruitcake. It's still good.
A fruitcake does not mold, or should not mold, assuming the cake has a much higher proportion of fruit to cake. One reason the cake should not mold is the amount of alcohol which is preserved by wrapping the cake up in layers of plastic and tin foil. If the cake is to be kept for long term, people wrap the cake in muslin soaked with booze, and then cover the thing in plastic and tin foil. Another reason the cake does not mold is because of the high sugar content. Apparently, sugars are resistant to molds, the butter and flour are susceptible to mold rather than the sugars.

A light bulb goes on in my head. Over time, puerh tea breaks down its cell walls to release the bitter juices which are converted to sugar via Rhizopus yeast which uses carbons from bacteria as food. As the tea sweetens with more and more plant sugars, the molds present in the tea decline over time until they die off at the end of decades of fermentation. A fully fermented puerh tea should have almost no bacteria or mold, because these are consumed by fermentation and replaced by plant sugars. Thus the puerh tea is safe to drink, and sweet rather than bitter.

I learned more about the nature of sugars in fruitcakes. Apparently, sugars with their crystalline structure are very hard, and hold water. If the fruitcake is appropriately moist, the structure of the sugars is loosened. But if the fruitcake dries out, the sugars want to return to hard crystals. Should a fruitcake dry out and harden, the sugars in their crystalline structure can be induced to release water and return to a moist state. To do this, one can heat the fruitcake in a dry low heat oven.


Wait...so, a dry, hard fruitcake actually returns to a moist fruitcake by heating in an oven, without adding more moisture? Apparently so, and this is because the sugars are holding the moisture.

I start to think about the overly-humid stored puerh cakes that get dried out like old autumn leaves. Of course vegetal matter has simple sugars, whereas a tighter sucrose sugar has an extra carbon and a more complex crystalline structure that holds water molecules. I did add about ¾ cup dark brown sugar to my fruitcake. 

But I wonder if added heat does more to reconstitute a dried out puerh cake than added humidity. Not to mention the musty mildew odor that can disappear with added heat. I have that dried out humid eBay fake tea donation from July…should’ve thrown it away, but didn’t. 

eBay Fake, from this post
Into the oven it goes.

I am not expecting this tea to turn into something miraculous, it is a health hazard more than anything else. However, I am curious to find out what changes, if anything, after an oven-bake. To reconstitute a fruitcake, a scientist recommends 140F (60C) for 10 minutes. I have a small oven to use (no way am I gonna fire up my expensive gas oven for a piece of crap) that has a lowest temp of 150F (65C), but tends to the cold side when using it for cooking. Close enough.

A rack seems like a good idea.
After ten minutes of bake time, I get a wafting odor of basement from the oven. I went twelve minutes, doubting whether this is enough time for the heat to completely penetrate the tea cake. Come to think of it, a dried out fruitcake is likely equally dense if not more so. I am going to try the outer leaves anyway, not the innards. I fire up the kettle.

Oven view.
The tea does not look any different in appearance after the oven, so I did not take another photo. As for my previous testing of this tea, I used 8g and the same Yixing pot. I threw away the first three rinses as before. I still smell some mildew basement in the Yixing, but much less than I remember.

Could be worse...
The brew is light and actually sweet. Not that unpleasant really. I still feel just a slight tongue numbing but if I can get past that, the tea is still a bit lively. Now the wet storage is at more of a perfect level: when a wetter stored tea has one part woodiness and one part humidity, to me that is just the right touch. 

I cannot discern whether the tea is actually made sweeter by the heating, or if the basement humidity is reduced enough to taste the sweetness which was already in the tea, but previously obscured. I do not recall seeing green in the leaves the last time, but perhaps I did not look closely enough in the sunlight to see. Maybe the cake is not quite dead.

I notice now the leaves still have some green.
One thing is certain to me now. If I have a tea with storage that I feel is a bit too much, I will definitely put the tea in the oven for ten minutes. After all, most rather wet teas are on the less expensive side, so I am not potentially risking a very fine tea. I will also consider the idea of using the oven to reduce any accidental white fuzz on tea. In fact, if tea is not yet a loss I might rehabilitate an experiment “gone too far” by oven heating. At such a low oven temp, I am not risking burning the tea. 

So, what did I learn from fruitcake that I can apply to tea? A fruitcake is actually more akin to wine, but has a maturation process fed by moisture. High sugar content and alcohol inhibit mold, and once tannins are released from the fruit, a complex balance of flavors emerge. This too happens with aged puerh as it converts bitter tannic juices to sugars. Those of us with a craving for complexity might find a fruitcake hobby satisfying, and certainly more rewarding in the short term as we wait years for our tea to mature. 


  1. Ever think about using one of these things?

    1. I've seen those marketed for oolong teas as a way to "re-roast" small amounts (like maybe 3g) for consumption. Or to remove a bit of storage humidity from oolong which can really make it sour. I have a sencha roaster which is a bit larger to use on the stove, but basically the same concept. The only reason I consider it appropriate for those teas is because it could really revive expensive oolong or sencha. Humid puerh, on the other hand, isn't usually worth the effort and time.

    2. I have a rolled oolong that I got for a big name company when I was in NY, at first it didn't taste good but after a year it really came into something. However it is sour-ish, but in a very complementing way (like a purple plum just before its ripe, so plummy with a sour back). My question is, should I roast it out and get the honey or keep it and stay with let it age for another year? At what time/temp should I roast if I were to? Thanks.

    3. I'm not really the person to ask, sorry, as I don't know much about oolong. However, you can always just try a few grams and roll them around in a hot pan for a few minutes. Most of what I have learned about puerh tea I learned from experimenting and failures.

  2. That fruitcake looks like one of my mother's. Now I'm in the US I really miss them.
    We used to make a big batch, in a big plastic tub, each year. One for Christmas, one for my birthday and one for my fathers.
    I don't remember her feeding them, but they were definitely laced with brandy and stored for the rest of the year.

    In the new year I'll have to make one for Christmas (maybe several for the next few years...)

    1. So you have her recipe then? Or maybe by heart :)

  3. Excellent post! Very interesting! This stimulates a variety of questions (materials scientist!).

    There is a big difference in the sizes of particles found in a fruitcake. There are small cakey bits, and bigger fruity bits. The alcohol will work on these differently, and they will also have different sugar structures, purely based on their nature. Additionally they will have many "boundaries", or spaces between particles, where interesting interactions will happen. This makes me wonder about the nature of puerh blending w.r.t. particle sizes. Perhaps this is why good blended cakes we see containing a variety of tea grades. Yeast will work on different sized leaves at different rates, and you will also get interesting boundary effects.

    Another difference worth mentioning is the amount of empty-space volume within the lattice, and what that empty space will contain. Initially a fruitcake will have more open space, within the spongey nature of the cake, that fills with probably viscous liquid/alcohol/sugar slurry which crystallizes into a denser sugar, or even retains some air content. I don't get the sense that there is much that fills the space between the leaves in a puerh cake, or if there is even enough space after compression to be worth discussing this "component" of a puerh cake.

    You also rightly mention that the molecular sugar content itself is different, which is important and I don't have enough experiences working with sugar molecules to appreciate these differences.

    I wonder ultimately if the sugar content within a puerh cake is high enough for heating to have more than a marginally significant effect. Close to consumption, perhaps. What about periodic heating as a supplementation to non-ideal storage conditions, in say the colder US climates? What about, instead of oven-baking, the pumidor is supplemented with an electric heating blanket, which can bring the temperature close to 140F for several hours every day? Is this how I will discover the fire-resistance of my puerh collection? Your pre-consumption heating experiment is interesting enough to bear repetition across several cakes of a collection, not just the driest.

    The ultimate question though is when are you going to start "feeding" your puerh cakes alcohol, which alcohol are you going to pick, and how long until you report on that experiment?

    1. Thanks for the comments! A friend with this same puerh cake heated his in the oven after reading this, and reported similarly the sour humidity flavors lessened and he could taste the tea better.

      I read that the best fruit cakes for maturing should have as little cake as possible, as the cake part is susceptible to mold but the fruit is not.

  4. And if your fruitcake gets moldy, gently brush it off or cut the faulted area!