|"Before" photo of 2013 Zhanglang Gushu, and 2012 Spring Bada Dashu|
Finding any kind of information online about pile fermentation is difficult. Most often I read how this process is a "carefully guarded secret," and "secret recipe" etc. But the more I think about this, I wonder what is so carefully guarded, when the process is simply a pile of tea moistened with water on a factory floor covered with a tarp? What is the secret, apart from sanitized conditions? Found a possible clue in a study by Hou, Jeng & Chen (2010), Journal of Food Science 75(1), H44-48.
In this study, the authors added a "tea extract" to the pile and compared an analysis of this sample with a sample fermented with water alone. The authors found statistically significant increases in levels of statin, GABA, gallic acid, DPPH scavenging and polyphenol oxidase (PPO) activities, whereas polyphenols and caffeine were decreased over 6 months. The authors also found qualitative differences of "enhanced flavor and taste." These changes were attributed to the increased population of A. niger and A. carbonarius at 6 months into fermentation. These are fungi which grow at 30 degrees C or above during the fermentation process. Even more important, once the teas were heat-dried, the authors found that the bacterial count in the tea extract sample returned to insignificant and safe levels.
I began to wonder about this "tea extract," whether this might be the so-called secret so carefully guarded by factories. Before now I had already concluded that factories are adding things to tea cakes, based on the large numbers of articles I read from the Journal of Yunnan University. All this research doesn't just happen in a university vacuum. Research is derived from observations of actual real life processes, and then university research in turn informs industry in a back and forth direction. In my blog previously, I have questioned whether it is even possible now for tea drinkers to isolate "regions" and "flavors" when drinking a tea cake. In fact, tea drinkers might be drinking flavors what the factories have intended for us to taste. And that this taste result is more than just a blend of leaves from various regions, but rather direct manipulation of the tea to enhance the flavors for a specific end taste. Some studies I've read identified the chemical compounds behind tea flavors, and manipulated tea to obtain these flavors, like "betel nut," or "plum."
Factories aren't disclosing whether or not the tea I'm drinking has been subjected to any sort of manipulation, unless the tea cake I'm buying is directly sourced by the vendor and raw, such as cakes produced under the supervision of Chawangshop, white2tea, Mandala Tea, Essence of Tea, Crimson Lotus Tea or Yunnan Sourcing, to name a few. Based on their first-hand reports, we know these vendors choose their tea leaves via tasting and then supervise the pressing of raw tea cakes. Often they may use small local or family-owned tea farms with woks, pressing stones and a few pieces of sorting equipment. In the cases of vendors like these, we know for certain how the tea is produced. Any manipulation of the tea is an expensive process that only factories are likely to engage in.
I also know from puercn articles that the government is asking directly what can be done to sell the large tonnage of leftover tea leaves, the ones that aren't gushu, and aren't particularly high end quality. One case in point is the still-leftover tonnage from 2008, one of the years most collectors try to avoid because of the over-harvested and weak leaf and because of a peak in pesticide and chemical fertilizer use at that time. An easy answer to dealing with leftover tonnage is to produce tea enhanced beyond its original flavor via processes like the addition of tea leaf extract. Another answer is to sell it to other companies who might manipulate the tea in more obvious ways, such as Teavana who might add flavorings, sugars etc and other herbs to create obvious blends.
But back to the extract and my own tea sample...I ask myself "what is a tea leaf extract?" A direct extract is pressing fresh tea leaves to squeeze out the natural fresh juice. This takes a lot of leaf. Anyone with a juicer knows how many vegetables you need to get a glass of fresh juice. Another extraction process is either a water extraction or alcohol distillation which is the method used in herbal medicines to obtain a tincture. Alcohol distillation is rather cumbersome, and expensive compared to either pressing fresh leaves or extracting the tea with water. If I had to guess, the least expensive method in real life which uses the smallest quantity of fresh leaf would be to simply brew up the fresh leaves in water. The idea here is then to use the tea soup to wet down the pile rather than just water alone.
I wish I'd done this with my sample from the beginning, since I've only been using water. Adding tea brew to my sample is easy enough to do, and why didn't I think of this sooner? But no reason I can't start now. So this past week I got out my freshest cake from 2014, and selected white2tea's Last Thoughts. By now plenty of loose tea has gathered in the cake wrapper from the couple of tastings I've done on that cake, so I scooped up some loose tea and brewed it up to add to my fermenting sample. Makes a lot of sense to me now to add fresh tea brew rather than just water to my pile. Adding anything which might control the bacteria and enhance the flavor, well why not? I've only had a few days now to observe any differences, which at this point are guesses at best. So far I have noticed the ferment-y odor starting to decrease in the pile.
At this point too, I think that time is still needed on the sample for further browning. A fermentation process eventually finishes out and I'm seeing the color fade. Looking at end-process pile photos online, I see that the finished tea is a lighter brown color when dried. Some of the pieces in my sample are at that point, but at least half the sample is not. Unless I start to see rapid change, I'm guessing my sample is around 50% fermented at best. Tea takes longer than sauerkraut.
Requiescat in Pace.
C. W. Hou, K. C. Jeng & Y. S. Chen (2010). Enhancement of Fermentation Process in Pu-Erh Tea by Tea-Leaf Extract. Journal of Food Science 75(1), H44-48.