The steps
Oolong is made in a fixed sequence: pluck, wither, make green, fix, roll, dry, and often roast at the end.
Wither first, either in sun for an hour or two or indoors on racks for longer.
Then comes the step the category is built on, called making green, or zuo qing（做青）.
Leaf is shaken in bamboo trays or tumbling drums, then left to rest, and the pair is repeated.
A typical session runs 3 to 5 shakings, each followed by a rest of 1 to 2 hours.
Across a night that is 8 to 12 hours of work, and it is what develops the aroma.
Fixing comes next, at a high pan or drum temperature, to stop the oxidation the shaking started.
Then the leaf is rolled into strips or into balls, depending on the style being made.
Drying follows, and many oolongs are roasted afterwards, sometimes twice, at perhaps 80 to 120°C.
A heavily roasted tea may be rested for months and roasted again before it is sold.
Between the two roastings the tea is left to settle, and most makers say it drinks better for the wait.
Order matters
The order is mechanical rather than ceremonial, and each step exists to make the next one possible.
Withered leaf is floppy, and only floppy leaf can be shaken without tearing into pieces.
Shake leaf that has not withered and you get broken edges that oxidise black within an hour.
Shaking starts the oxidation by bruising the leaf rim, and fixing exists to stop it at the right moment.
Fix before shaking and there is nothing to stop, because no oxidation has begun yet.
Fix after rolling and the leaf has gone too far, since rolling spreads the damage through it.
Rolling then shapes a leaf whose chemistry has already been set, which is the whole point.
Roasting comes last because it is a finish, and roasting first would seal the leaf before it developed.
Every step hands the next one a leaf in a particular state, and there is no way to skip ahead.
This is why the sequence survived centuries of tinkering, and not because anyone insisted on it.
Where it can go wrong
Most bad oolong is one step done too fast, too hot or too long, and the fault is usually visible.
Under-withered leaf tears in the drum and gives a dull, leaf-green tea with no aroma.
Over-shaken leaf goes red at the rim and then sour, because the oxidation ran past its window.
Under-fixed leaf keeps oxidising in the bag, and the tea turns red and flat within weeks.
Over-fixed leaf locks in a raw green note that no amount of roasting will remove later.
Roasting too hot scorches the outside of the leaf while the inside stays unfinished.
Roasting too long flattens everything, and you end up tasting charcoal rather than tea.
Rushing the rest between shakings is the commonest shortcut, since it saves hours of floor space.
A maker cannot fix any of these afterwards, which is why the process is watched rather than timed.
Timing is the second half of the skill, and it is the half that machines still do badly.
Fixing is decided in minutes, and a whole night of making green depends on that one judgement.
Scale and consistency
The same steps run in a workshop making 20 kilos and in a factory making 2 tonnes a day.
What changes with scale is not the method but the ability to hold it steady.
A workshop can judge each tray by hand, and a factory has to standardise the conditions instead.
That means controlled rooms, since withering and making green both depend on temperature and humidity.
Large producers use air conditioned making rooms to keep the leaf inside a narrow band overnight.
Blending is what makes consistency possible, since one batch alone rarely matches the house style.
A factory tea is therefore more even and often less interesting than a small lot.
Machines now handle tumbling and rolling, and they do it more evenly than a tired worker.
What they cannot do is decide when to stop, which remains the maker’s judgement.
Scale buys consistency, and it charges for that consistency in character.