Shu Pu'er — The “Foundation” Trilogy, Part III

Shu, also known as ripe, “dark,” or cooked pu’er, is the closest relative of sheng pu’er, yet at the same time its polar opposite. If sheng is about a bright infusion and a fresh, “green” taste, then shu ranges from light red to dark, oil-like black, with a dense, rich, woody-chocolate-nutty-creamy profile.

Much of the information from the previous post about sheng applies equally to shu, since they share the entire production process up to the stage of mao cha (“rough tea”). The only difference is that, before being pressed into cakes, mao cha may undergo an additional stage called wo dui.

Wet Piling (wo dui, 渥堆)

Mao cha is laid out into piles (heaps) up to half a meter high in a room with continuous air circulation and is generously moistened with water (30–50 liters per 100 kg of raw material), covered with cloth on top — this initiates a process of wet fermentation similar to composting. As a result of biochemical activity by microorganisms and fungi, particularly Aspergillus, the piles heat up to 40–70°C and acquire a dark brown color.

The technician carefully monitors such variables as the ratio of raw material in the blend, temperature, humidity, and duration of the process, while also regularly turning the piles to ensure even fermentation. Tea samples are taken to observe its condition. Wo dui may take from one and a half to three months, depending on the type of raw material.

The set of variables described above can be repeated year after year in an identical manner, effectively becoming a recipe. On one hand, recipe-based shu can be useful, providing a conditional guarantee of a certain outcome; on the other, no two teas are ever exactly the same.

Wo dui may be carried out in the classical manner or in small-volume baskets. In the first case, factory production usually works with 3–6 tons of piled tea at once. In the second scenario, smallholder farms typically process only 300–500 kilograms, distributed across a dozen or so small baskets — this allows for a much more controlled fermentation process, and as a result, the raw material chosen for basket fermentation is usually of a higher grade.

Many producers add a pinch of fresh sheng to nearly finished piles, which can sometimes be noticed in the leftover leaves after drinking — this is done to enrich the flavor-aromatic palette with a liveliness and play of tones that shu on its own does not fully possess.

If in sheng the key factor is the quality of the raw material, then in shu it is the skill of the technician controlling fermentation.

This is because the deep degree of processing significantly transforms the mao cha, and the characteristics of the original leaves are not as distinctly traceable in the finished tea as they are in sheng. For this reason, most shu pu’er is produced from plantation material — and there is nothing shameful in that.

Wo dui was developed in 1973 at Kunming University under interesting circumstances: technicians, notably Wu Qiyin, were faced with the challenge of not waiting 20 years for sheng to fully mature, and sought an alternative approach to achieving a similar outcome. Borrowing from the technology of other dark teas (hei cha), the masters pushed key variables (humidity, temperature) to their maximum and applied them to Yunnan raw material. However, the attempt to produce an “imitation” of natural aging ultimately resulted in the creation of an entirely new type of tea — one that takes not decades to produce, but less than a single year.

Variations of Shu Pu’er

→ Leaf/Bud Ratio. The higher the proportion of buds, the more juicy, sweet, and deep the liquor will be, whereas leaves set the overall profile and thickness of the infusion. Gongting refers to tea with an elevated bud content.

→ Cha Tou (“tea nuggets” or “tea heads”). Large, densely compacted chunks of tea formed naturally during the wo dui process, which are collected separately. Because of their density and size, such tea is not merely steeped but rather simmered or boiled to extract its essence.

Pressing

After the completion of wet piling, shu is dried and aired, after which — as with sheng — it is steamed, placed into cloth bags, and pressed either manually or by machine. The types and degrees of compression in shu pu’er follow the same categorization as in sheng. However, an interesting fact is that loose shu, unlike loose sheng (mao cha), is officially recognized as “pu’er” at the legislative level. A convention, but an unusual one!

Aging

Unlike raw sheng, which conditionally requires 10–15 years of aging to reach the peak of its depth, shu is a finished product immediately after pressing, and post-fermentation has a somewhat different effect on it. In rare cases of perfectly executed wet piling, shu may indeed be ready to drink immediately after pressing — therefore, I recommend choosing cakes with 1–2 years of resting time, during which the fermentation aroma has had a chance to balance out. By years 3–7, a cake usually reaches its peak, delivering the juiciest and most vibrant results. Subsequent aging, extending up to 20+ years, gradually softens and harmonizes the flavor-aromatic profile, adding complex and unique notes — old shu is something one learns to appreciate over time; it is not advisable to rush into acquiring collectible aged cakes right away.