Sheng pu-erh
A green tea route with one substitution — sun-drying instead of oven-drying — and that substitution is why a cake can change for decades instead of going stale.
What makes this route what it is
One substitution at position five. Every other route in the catalogue takes its tea to a stable finished state; this one deliberately stops short, and every subsequent step — the loose holding, the slow cake drying, the porous wrapper, the warehouse — is designed around keeping that unfinished state alive rather than around protecting a finished product.
The route, in order
Each note describes what the step is doing in this route. The same operation does a different job in a different chain.
Large-leaf assamica material, often from old or semi-wild trees, picked to a coarser standard than a fine green tea. The route needs substance that will still be there in twenty years.
Short and light, mainly to make the leaf handleable. Not the long chemical wither of a black tea and not the extended one of a white.
Run cooler and deliberately less completely than for a green tea. The intention is to arrest most of the oxidation while leaving some enzymatic capacity in the leaf, which is a decision, not a shortcoming.
Twisting to rupture cells and set a loose strip. Heavier rolling gives a faster-changing maocha, which is a real lever on the finished cake's trajectory.
The substitution the whole category rests on. Low-temperature drying in the open leaves the leaf unfinished, and everything downstream exists to look after that.
Loose holding between manufacture and pressing, which may be days or years. It is why a wrapper's year is a pressing year and constrains the leaf's age only from above.
Spring material pressed within weeks is common for single-area cakes, where the point is precisely that nothing has been held or blended.
Seconds of steam to make the leaf pliable. How long is a genuine argument in the trade, because the steam is the only part of cake-making that acts on the leaf chemically.
A loose cake with internal void space, which breathes and matures more evenly than a dense one.
Hydraulic pressing gives a dense, square-edged cake that holds its young character longer. Producers pressing for early drinking often choose it deliberately.
Days to a fortnight on racks in shade. The steam has to leave a compressed mass slowly, and a heated drying room here undoes much of what step five was for.
Porous cotton paper, bamboo husk, stacks of seven. Storage conditions rather than packaging, chosen so that air and humidity keep reaching the tea.
Years to decades, and the only step that happens after the tea has left the producer. It is the reason all ten previous steps were run the way they were.
How it differs from its neighbours
A route described on its own teaches very little. The useful fact is always which other route it is nearly identical to, and where it leaves it.
One position in the route is filled by a different named method. The shape of the route is unchanged.
Sun rather than oven, at the drying slot. It is the most consequential single substitution in the whole catalogue: the same leaf, fixed and rolled the same way, becomes either a tea that is best in its first year or a tea that is worst in its first year.
The two routes are the same tea up to a point. Everything before the divergence is shared; everything after it is not.
Identical for five steps. At step six one route holds the maocha and presses it, and the other wets it and ferments it for weeks. Everything the trade argues about when it argues about shou turns on that one fork, and nothing before it differs at all.
Where it goes wrong
A fixation run too hot destroys the capacity the sun-drying was meant to preserve, and the cake never develops; the tea is drinkable, pleasant and permanently young, and the fault is invisible for about five years. Drying maocha in an oven because the weather turned does the same thing more thoroughly, and a cake pressed wet and dried in a heated room adds a mould risk on top of it.
In full
For its first four steps sheng pu-erh is made almost exactly like a Chinese green tea: withered briefly, fixed, rolled. The differences are matters of degree — the fixation is run deliberately cooler and deliberately incomplete, so that some enzymatic capacity survives — and they would be details if it were not for what happens next. The leaf is spread on mats in the open and dried by the sun at low temperature. An oven takes a green tea to storage dryness and effectively finishes it; sun-drying does not, and the maocha that results still carries residual enzymatic and microbial capacity. That single difference is the whole basis of the category. The tea is then held loose for a period that may be days or years, steamed, pressed, dried slowly, wrapped in porous paper and bamboo, and stored — and it keeps changing throughout, which is what everybody who buys it is buying.