Processing
77 production steps, in the order leaf moves through them. In coffee, processing adjusts the flavour of a bean that was already going to be coffee. In tea, processing is what decides the category — the same leaf becomes green, oolong or black depending on when heat is applied.
The steps in order, as whole routes
This page lists the operations. What it cannot show is that the ORDER is what makes a category: green tea and black tea share nearly every step and differ in when heat is applied. The production routes lay each chain out step by step and name the point at which each one departs from its nearest neighbour.
1. Plucking
7 stepsWhat is taken from the bush, and what was done to the bush before it was taken. The picking standard sets a ceiling on everything downstream — no later step recovers what was not picked.
The decision, taken at the factory door, about which intake becomes which product — and the point at which a day's leaf is split into separate lots that never meet again.
The hours between the bush and the factory door, during which a packed bag of leaf can heat itself and start changing before anybody has decided what it should become.
Picking each shoot individually by hand, which is the only method that can choose what to take and what to leave.
Breaking each freshly picked shoot apart by hand so that the individual leaves go forward and the bud and the stem are set aside.
Cutting the top of the plucking table with a powered blade, which takes everything at a set height regardless of what is ready.
The rule about how much of each shoot is taken — bud only, bud and one leaf, bud and two, or mature leaf — which is set before any factory decision is made.
- Shading被覆栽培
Covering the bushes for days or weeks before plucking, which changes the leaf’s composition before it is ever picked.
2. Withering
5 stepsMoisture leaves the leaf and it goes limp enough to handle without shattering. Chemistry starts here too, which is why withering is a decision rather than a wait.
How far the wither is allowed to run, which is a separate decision from how it is carried out and shapes the tea more than the equipment does.
Part-way through a white tea wither, the contents of two or three sieves are tipped into one, thickening the bed so the last of the wither runs slower and warmer.
Withering leaf outdoors under direct sun for a short, closely watched period — the opening move of oolong, of white tea and of pu-erh maocha.
Withering on a mesh bed with fans forcing conditioned air through the leaf, which turns a weather-dependent step into a scheduled one.
Controlled moisture loss that makes the leaf pliable and begins its chemical change.
3. Bruising
2 stepsCell walls at the leaf edge are broken deliberately so that oxidation begins where the maker wants it and not elsewhere. This is where oolong gets its red rim.
Deliberate, repeated agitation that damages the leaf edges so oxidation begins there and nowhere else.
A small green leafhopper feeds on the growing shoot and the plant answers. The answer is the raw material: shoots that have been fed on are picked in that state, and a tea made from undamaged leaf on the same bush is a different tea.
4. Oxidation
5 stepsEnzymes in the ruptured leaf react with air, darkening the leaf and rebuilding its aroma from the ground up. How far this is allowed to go is the single biggest fork in the whole sequence.
The oxidation slot, run with the air taken out. Withered leaf is sealed into a vessel from which oxygen has been displaced and held there for hours, and the schedule of holds and airings is the manufacture.
The room and the equipment in which oxidation is actually run — cool, saturated, ventilated, and judged by nose rather than clock.
A short heaping of the leaf at the end of the shaking cycles, used to push the last of the oxidation quickly before the heat goes on.
The enzymatic browning of ruptured leaf that turns green tea material into black tea material.
The quiet hours between one shaking and the next, which is when oolong actually oxidises — the shaking only decides where.
5. Fixation
5 stepsHeat denatures the enzymes and stops oxidation dead. The moment fixation happens decides whether a leaf becomes green tea, oolong or black tea, and it cannot be undone.
Kill-green in a heated rotating cylinder that leaf passes through continuously, which is how most Chinese green tea is now fixed.
Heating the leaf to stop oxidation — the step that makes green tea green.
Fixation by direct contact with a heated wok or drum, which halts oxidation and toasts the leaf at the same time.
Getting the heat out of the leaf immediately after a hot step, because heat that stays in the leaf keeps cooking it after the operator has stopped.
Fixation by live steam rather than dry heat — the choice that separates Japanese green tea from Chinese.
6. Yellowing
2 stepsA slow, damp, sealed rest applied after fixation. It is not oxidation and it is not fermentation, and it is the only thing that makes yellow tea yellow tea.
The slow smothering step that makes yellow tea, and the only step that separates it from green.
Whether the smothering step is done on damp leaf straight from fixation or on part-dried leaf, which is the main axis separating one yellow tea from another.
7. Rolling and shaping
17 stepsThe leaf is twisted, pressed, rolled or cut into the form it will be sold in. Shape is not decoration: it governs how fast the leaf gives itself up to water.
Combining lots so that a named tea tastes the same in March and in October, which is a manufacturing step performed on finished tea and not a compromise applied to it afterwards.
Wrapping leaf tightly in cloth and repeatedly kneading and unwrapping it until it forms tight spheres.
Leaf passed through counter-rotating toothed rollers that cut it into small uniform granules.
Rubbing warm leaf between the palms into loose balls and breaking them apart repeatedly, which curls the leaf into spirals and lifts its down to the surface.
Separating stem and leaf vein from the leaf blade after drying, usually by air separation.
Pressing leaf flat against the side of a heated wok by hand during pan-firing.
Shaking fixed leaf along heated parallel grooves until each piece straightens into a needle, rather than twisting it into a curl.
The older manufacturing route, in which leaf is twisted and rolled rather than cut, so it survives largely intact.
Working rolled leaf against the wall of a heated pan through successive pans until each piece closes into a hard sphere, drying and shaping in the same operation.
The second factory. Japanese green tea leaves the producer as aracha, an unfinished trade good, and is cut, sorted and separated elsewhere into the several named teas one intake contains.
Rolling is done in two or three passes with the compacted lumps broken up and sifted between them, because one long pass tightens the outside of a ball of leaf and never reaches the middle.
Working the leaf to rupture its cells and give it a form that governs how it later brews.
- Rotorvane macerationDefines Black tea
A screw press with internal vanes that macerates withered leaf continuously, sitting between orthodox rolling and CTC rather than belonging to either.
Separating dried tea by particle size, density and colour into the grades it is sold as — a sorting operation, not a quality judgement.
Hand removal of stalk and yellow leaf from finished oolong, done between roasts rather than at the end — which is why it is an ordering fact and not a tidying-up one.
Grinding de-stemmed tencha into powder between slow-turning granite wheels.
Rolling leaf into long twisted strips rather than compressing it into balls.
8. Fermentation
6 stepsGenuine microbial action, by fungi and bacteria rather than by the leaf's own enzymes. Only a small number of teas go through it, and the word is misapplied to almost everything else.
Packing steamed leaf into a sealed vessel and excluding air, so lactic acid bacteria rather than moulds carry out the fermentation.
Deliberately cultivating Eurotium cristatum on compressed dark tea until visible golden spores develop.
Wuzhou’s own microbial piling process for Liu Bao, which shares a family with pu-erh wet-piling and is not the same operation.
The scheduled turns that redistribute a fermenting heap, which is how a pile is steered — the temperature at its core is the whole control system.
Deliberate microbial fermentation of finished leaf under heat and humidity — what makes shou pu-erh.
The measured addition of water to dry maocha that starts a wet-piling fermentation, and the single decision that most determines what the finished shou tastes like.
9. Pressing
6 stepsLeaf is compressed into cakes, bricks or nests. Originally a transport decision, now also a storage one, because a compressed cake ages differently from loose leaf.
The paper, the bamboo shell and the stack are part of how the tea ages, not packaging around a finished object — and the wrapper is also the document.
Steaming loose leaf and pressing it into cakes, bricks, nests or logs — originally for transport, now for ageing.
Steamed dark tea rammed into a woven casing and compressed by rolling and treading the whole column, producing a tea shaped like a pillar rather than a cake.
- Pounding to a paste (mortar-beaten leaf)Defines Dark tea and pu-erh
Hot steamed leaf beaten in a mortar until it stops being separate leaves and becomes one mass, which is then formed by hand. The output of the step is a paste, not a shape.
Dry leaf is briefly steamed so it can be compressed without shattering — a few seconds too many and the cake has been part-cooked before it starts its life.
Forming a cake under a shaped stone weighted by a person standing on it, which gives a looser cake than a hydraulic press does.
10. Roasting
7 stepsApplied heat after the tea is otherwise finished, used to develop sweetness and depth or to reset a tea that has picked up moisture. A separate act from drying, with a different purpose.
Slow roasting over charcoal in baskets, in repeated sessions separated by weeks of resting.
Roasting in a temperature-controlled electric oven rather than over charcoal.
The last heat a Japanese green tea receives, applied at the refiner rather than the grower, and the lever that decides whether a sencha reads as fresh and grassy or sweet and toasted.
A short, hot roast applied to finished Japanese green tea, which converts it into a categorically different drink in minutes.
A light low-temperature bake applied to already-finished tea to drive off absorbed moisture.
Weeks or months of doing nothing between one roast and the next, during which the raw fire note recedes and the maker finds out what the roast actually did.
- Roasting焙火
Applying sustained heat to finished leaf to build toasted character, reduce moisture and stabilise the tea for keeping.
11. Drying
6 stepsThe final removal of moisture that makes the tea stable enough to keep. How it is done — sun, oven, basket — leaves a signature the drinker can taste.
Drying leaf in a woven basket over a low charcoal or electric heat source rather than in a pan or a hot-air machine.
- Drying乾燥
The final moisture reduction that halts change in the leaf and makes the tea stable enough to keep.
A freshly pressed cake is wet in the middle, and how that moisture is taken out over the following days is one of the least visible and most consequential decisions in dark tea.
A final drying method in which a basket of tea is carried over an intense charcoal fire for a second or two at a time, again and again, by a relay of workers.
Drying leaf in sunlight rather than in a machine, leaving residual enzyme and microbial activity intact.
Drying in two passes with a cooling interval between them, because moisture inside the leaf needs time to migrate to the surface.
12. Scenting
5 stepsFinished tea is brought into contact with flowers or other aromatics so it takes up their aroma. Where it is done carefully the flowers are removed afterwards and none of them reaches the packet.
A flavouring preparation is metered onto finished dry tea while it tumbles, and the lot is then left to equalise. It is not scenting, and the two are constantly confused because the finished packets look alike.
Hollowing a mandarin, packing it with dark tea and drying the whole fruit, so peel and tea age together in one object.
Between every scenting round the spent flowers are screened out and the leaf is re-dried — and the last round of all is a short one whose flowers are deliberately left in or taken out depending on the grade.
Withering and drying leaf over a smouldering pine fire so smoke volatiles are absorbed into it — the step that makes smoked Lapsang Souchong.
- Scenting窨製
Layering finished tea with fresh flowers so the leaf absorbs their aroma, then removing the spent flowers.
13. Ageing and storage
4 stepsDeliberate storage over years, during which a tea keeps changing. It is the one stage that continues after the tea has left the producer, which makes it the only one a drinker participates in.
Deliberate long-term storage under which a finished tea keeps changing, rather than merely keeping.
Ageing dark tea packed into woven bamboo baskets, which contribute aroma and regulate airflow.
Sun-dried maocha is frequently kept loose for months or years before anyone presses it, which means a cake's date is the date of its pressing and not of its leaf.
The deliberate two-phase Hong Kong practice of holding cakes in a humid warehouse and then airing them in a dry one for years before sale.
Why the order matters more than the list
No tea passes through every stage above, and the ones it does pass through are not all equally consequential. What separates the six categories is mostly a matter of timing: fixation applied immediately gives green tea, fixation withheld until oxidation has run gives black tea, fixation applied part-way gives oolong. Same leaf, same steps, different order and different duration.
This is also why the vocabulary is worth getting right. Oxidation and fermentation are two different processes and only one of them involves microbes, but the industry has called oxidation “fermentation” for a century and the confusion is now printed on packets. Each step page says where its own term gets misused.