Aerobic mould-fermented bancha
Japan's other fermented tea, and the one that does the opposite of the pickled teas: it lets the air in. The leaf is heaped after fixation and a mould is allowed to grow through it in the open, with nothing sealed and nothing weighted.
What makes this route what it is
It is the aerobic half of a pair that the English word fermented collapses into one thing. Everything about the route follows from admitting oxygen instead of excluding it: no weight, no seal, no liquid, no acidity, mould rather than bacteria, and a turning schedule instead of a standing time. Read beside `seq-s32f-pickled` it is the sharpest demonstration the catalogue has that a microbial step is not one step.
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.
Coarse mature bancha leaf. As with every fermented tea in the catalogue, the route is built around cheap substantial material rather than around a fine pluck it would waste.
Fixation before anything microbial is invited in, which is what makes this a post-fermented tea rather than an oxidised one. The leaf's own enzymes are stopped first and everything that follows is done to it by organisms.
An open heap in a room, at ambient humidity, with no water added and no cover sealing it. Moulds establish on cooked leaf that is still carrying the moisture of fixation. The same record as the pu-erh pile and a different operation inside it — nothing is wetted here, and the heap is smaller, cooler and slower.
Turning to keep oxygen reaching the interior. In a shou pile the turn also drops a dangerous core temperature; here the heap never gets hot enough for that to be the reason, and the turn is doing one job rather than two.
- 5.
Drying
The heap is opened out and dried, which stops the fermentation by removing the moisture the moulds were living on. The same operation as a turn, performed until it becomes an ending.
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.
This route leaves out an operation the other performs. Omissions are usually irreversible — the step cannot be added back later.
The anaerobic step is absent. In the pickled route the open mould heap is an OPTIONAL first stage that some productions run before the barrel; here it is the whole of the fermentation and there is no barrel at all. Two Japanese teas made a few hundred kilometres apart, one of which excludes air as its defining act and one of which admits it, and the reason they were sharing a record is that English has one word for both.
One position in the route is filled by a different named method. The shape of the route is unchanged.
The same aerobic mould heap, reached from the opposite direction. A shou pile is built from dry sun-dried maocha that has to be wetted before anything can live in it; this heap is built from leaf that is still wet from fixation and needs nothing added. One is a controlled industrial process on tonnes and takes weeks at a temperature that has to be managed; the other is a room in Toyama.
Where it goes wrong
An unturned heap goes anaerobic in the middle whether or not anybody intended it to, so the interior sours while the surface moulds, and the two halves cannot be blended into a coherent tea afterwards. The opposite failure is a heap kept too dry or too cool, in which nothing establishes at all and the leaf simply goes stale over several weeks of doing nothing.
In full
Two Japanese post-fermented traditions survive in quantity and they are usually described with one word, which is how the catalogue ended up describing them with one route. They are opposites. The Shikoku teas exclude air, seal the mass under liquid, weight it and let lactic acid bacteria acidify it; the Toyama tea does none of that. Fixed leaf is heaped in a room, moulds establish themselves aerobically, the heap is turned so that oxygen keeps reaching the inside of it, and after some weeks it is dried. Nothing is sealed, nothing is weighted, and no liquid is added. The organisms are therefore completely different and so is the result: this tea is not sour. It is the mould-fermented member of the family, and the closest thing to it in the catalogue is not the pickled tea it has been filed beside but the Chinese wet pile that makes shou pu-erh, which is also an aerobic mould heap and which is also turned for the same reason. The tea's other distinction is a preparation rather than a manufacture — it is the only Japanese tea other than matcha that is whisked, beaten to a foam with a twin-headed bamboo whisk in a wide bowl, sometimes with salt, and drunk at neighbourhood gatherings.