Nothing is added, so nothing is concealed
A black tea’s character is largely built during oxidation, which means an ordinary leaf can be turned into a respectable tea by running the process well. A roasted oolong gains a whole additional layer of flavour after the tea is otherwise finished. Green tea has neither. What arrives at the factory is essentially what will be in the cup, minus whatever the process takes away. The maker’s job is preservation rather than construction, and preservation is unforgiving: there is no later stage at which a thin start can be compensated for, and no aromatic layer to distract from a flaw. The same logic explains why green tea is so sensitive to the field. A poor picking standard shows immediately, a banjhi-heavy intake shows immediately, and material from the wrong part of the season shows immediately. Black tea manufacture can absorb a good deal of that and produce a serviceable tea; green tea manufacture simply carries it through to the cup.
The window on fresh leaf is measured in hours
Because green tea must be fixed before oxidation gets going, the interval between plucking and heating is short. That has consequences all the way back up the chain: the field cannot be far from the factory, the intake cannot be piled deep, transport cannot be slow or hot, and the factory cannot take in more leaf than it can fix within the window. A black tea factory can accept leaf all day and wither it overnight. A green tea factory that over-buys has leaf sitting in a heap warming up and beginning to change, and that leaf makes a duller tea no matter what is done to it. It also caps how big a fine green tea operation can be. A wok holds a small quantity and a skilled pair of hands can only work so many batches in a spring day, so premium production is bounded by the number of people who can do it during the few weeks the leaf is right. This is the real constraint behind pre-Qingming pricing, and no amount of demand relaxes it.
Fixation has no safe setting
The kill-green step has to be hot enough to denature the enzymes quickly and even enough to do it to every leaf in the batch. Too cool or too brief and some leaf keeps oxidising, so a tea that is supposed to have stopped continues to change in the packet and turns dull and yellowish over weeks. Too hot or too long and the leaf scorches, contributing a burnt note that never leaves. And unevenness is worse than either extreme, because a batch containing both under-fixed and scorched material cannot be corrected by any adjustment. This is the single hardest operation in tea to do consistently by hand, and it is the reason mechanised drums are used even by producers who do everything else traditionally. There is a further difficulty that makes it harder than it sounds. The right setting depends on the intake, and the intake changes: a wetter morning’s leaf, a coarser picking, a different cultivar in the next basket all need slightly different treatment. A fixed temperature and a fixed dwell time are correct for one batch and wrong for the next, so the operation has to be adjusted continuously against material that nobody has measured.
Shaping happens while the leaf is still changing
For the highly shaped Chinese greens, fixation and shaping are not separate stages. A Longjing maker fixes and flattens in one continuous set of movements against the hot wok wall, adjusting temperature by moving the leaf and adjusting pressure by feel, for as long as the batch takes. A Bi Luo Chun maker rubs the warm leaf into balls and breaks them apart dozens of times as it dries. The window in which the leaf is warm and pliable enough to shape and not yet dry enough to break is not long, and everything has to happen inside it. There is no equivalent operation in any other category with this much simultaneous judgement. The skill involved is also genuinely scarce rather than rhetorically scarce. It takes years to learn, it is learned by doing rather than by instruction, and it is seasonal work that pays for a few weeks a year. Producing regions across China report the same difficulty in finding people willing to acquire it, which is one of the quieter reasons machine-shaped tea has spread even where the market would pay for hand work.
And then it starts declining immediately
Green tea is the least stable finished tea. Its character depends on volatile compounds and on an unoxidised leaf that would very much like to oxidise slowly given warmth, light, moisture or air, and it loses its best qualities over months rather than years. So the difficulty does not end at the factory: a spring green tea has to be dried properly, packed promptly, kept cool and drunk within a reasonable period, and every link in the chain from producer to shelf to cupboard can undo the work. Much of what people describe as not liking green tea is a description of stale green tea. This is where the earlier steps come back. A fixation that was slightly incomplete leaves residual enzyme activity, and that tea will stale visibly faster than one fixed properly; a drying that stopped a little short leaves moisture that does the same. So the instability everyone attributes to the category is partly inherent and partly a record of how carefully the tea was made, which is why well-made green tea keeps noticeably better than the average.
Why the finest Chinese teas are green anyway
None of this stops green tea being the category with the highest peaks. The same absence of concealment that makes a mediocre green tea obviously mediocre makes an excellent one extraordinarily direct: there is nothing between the drinker and the leaf. That is why the Chinese domestic market prices pre-Qingming green teas as it does, and why so much of the vocabulary of fine tea in China concerns freshness, picking dates and the number of days between plucking and drinking. The category has the narrowest margin for error and the least to hide behind, and that is precisely what its admirers value about it. It follows that green tea is the worst category to judge from a supermarket shelf and the best one to judge from a producer you can date. Where the picking date, the drying and the time since are all known, the tea is meeting you on its own terms. Where none of them is known, an unremarkable cup is evidence about the supply chain rather than about the tea.