The control points
Dark tea has the longest process in tea, and its control points are spread over weeks or months.
Fixing comes first, and it is done at a lower temperature than for green tea on purpose.
The aim is to stop the leaf going green without destroying everything the fermentation will need later.
Rolling follows, and for raw pu-erh it is light, since the leaf has to survive years of change.
Sun drying is the third point, and it is what separates raw pu-erh from a green tea.
Piling is the fourth and the largest, used for ripe tea, and it runs on moisture, heat and time.
Water is added to bring the leaf to roughly 30 to 40 per cent, and the heap is built from several tonnes.
Temperature inside the heap is held between 50°C and 60°C and monitored every day.
Turning is the fifth point, done 7 to 10 times over 30 to 60 days, and each turn resets the heap.
Drying and pressing follow, and the moisture at pressing decides how tight the cake ends up.
Storage is the last control point, and over decades it outweighs everything that came before it.
Why they matter
These points matter because the fermentation is biological, and biology is far less forgiving than heat.
A heap that runs too wet turns sour, and sour ripe tea never recovers in storage.
A heap on the dry side stalls, and the tea comes out harsh and green in the middle.
Temperature above 65°C kills the organisms doing the work, and the pile stops changing.
That produces tea tasting more like weak raw pu-erh than ripe, which is a specific and common fault.
Below 40°C the wrong organisms take hold, and the result is musty rather than sweet.
Turning controls both, and it is also the only chance to even out a heap that has developed hot spots.
Fixing temperature matters for raw tea in the opposite way, since too much heat ends the ageing before it starts.
A raw pu-erh fixed too hot stays almost unchanged for 20 years, which is not what buyers are paying for.
Pressing moisture matters less than people think, though a very wet cake can mould in the first year.
Storage humidity between 50 and 70 per cent is the range most traditional cellars aim for.
Signs of trouble
The faults in dark tea divide neatly between the pile and the store, and the smell tells you which.
Sourness in ripe tea means the pile was too wet or ran too long, and it does not age out.
A musty or cellar smell means the storage was too damp, and it affects raw and ripe alike.
A harsh, bitter young ripe tea means the fermentation was cut short, leaving the raw character behind.
A muddy, dull liquor points to a pile that ran too hot and killed the fermentation part way through.
White or grey spots on a cake are not always jin hua, and stray mould smells different from the controlled growth.
Jin hua smells faintly sweet and appears inside the brick, while unwanted mould sits on the surface and smells damp.
A cake that tastes of nothing at all was probably stored too dry, and 10 years has done nothing to it.
Loose leaf that has lost its aroma entirely has usually been stored in the open rather than wrapped.
Brew 6 grams at 100°C and take it through 6 infusions, since faults appear late as often as early.
If the smell is clean and the sweetness holds, the pile and the store were both managed.
Holding the standard
Holding the standard over a 60 day pile is mostly a matter of records and discipline.
Heap temperature is probed at several depths each day, and the reading drives the decision to turn.
Moisture is checked at each turn, and water is added back when the heap has dried out.
The turn count and the day count are what a buyer should ask for, since 30 days and 60 are different teas.
Producers who pile in smaller heaps can intervene faster, which is why small batch ripe tea varies more.
Large heaps hold heat better and forgive a missed day, at the cost of less control.
After pressing, storage is the discipline that decides whether any of that work survives.
A warehouse needs stable humidity and some air movement, and the best ones are checked rather than assumed.
Traditional cellars in Guangdong run warmer and more humid than those in Kunming, and the tea reflects it.
Buyers should ask where a cake has been stored, because by year 10 that matters more than the district.
The pile decides what the tea can become, and the store decides whether it gets there.