What gets picked
Yellow tea is picked to a green tea standard, which means bud and very young leaf.
Junshan Yinzhen is a single bud, and Mengding Huangya is a bud with 1 leaf.
Fat buds are the requirement, because a thin bud cannot survive what comes next.
The standard is stricter than green tea in one respect: the buds must be uniform in size.
Mixed bud sizes cannot be damped evenly, and uneven damping is the commonest fault in the category.
Pickers work slowly for this reason, selecting individual buds rather than stripping the bush.
The yield is tiny, which is the main reason yellow tea is scarce and expensive.
Some 4 or 5 kilos of fresh buds are needed for 1 kilo of finished tea.
Old leaf and stem have no place here, and a lot containing them is not yellow tea in practice.
The pluck is the easiest place to see why this category costs what it does.
A single picker might gather 2 or 3 kilos of usable buds across a whole morning.
Why the standard exists
The reason is the damping step, called men huang（闷黄）, which is what makes a yellow tea yellow.
Hot leaf is wrapped or covered while still damp, and held for hours at a warm temperature.
That slow, damp hold is what removes the grassy edge and develops the sweetness.
It only works if every piece of leaf is at the same stage, because the process is gentle and even.
A thin bud dries out while a fat one is still holding water, and the batch comes out uneven.
Old leaf does not yellow at all, since the chemistry that produces the change has slowed by then.
So the plucking standard is what makes an even damp possible, rather than a mark of luxury.
The process is also unforgiving, because leaf held too long in that state turns sour.
A uniform pluck gives the maker one moment to judge, while a mixed one gives no moment at all.
This is the clearest case in tea of a plucking standard dictated entirely by a single step.
Grade follows the leaf
Grade in yellow tea is almost entirely a judgement about buds, and it is made in the field.
Size, fatness and evenness are the three things a grader looks for in the dry leaf.
Down on the bud is a good sign, since it indicates young material handled carefully.
Colour counts too, since an even yellow-green is right and grey or dark buds are not.
Broken buds are heavily downgraded, because breakage means the material was mishandled.
A lot with leaf mixed through it cannot be sold as a bud grade, whatever it tastes like.
Machine plucking is not used for the top grades, since it cannot select buds.
Because volume is so small, grades are usually assigned by the producer without any outside check.
Two producers using the same grade name may mean quite different material, so compare the leaf.
The honest test is the cup next to a green tea, since that is where grading gets exposed.
If the two taste the same, the grade on the box was describing appearance and nothing more.
Season and timing
Yellow tea has the shortest useful window of any category, and it falls around early spring.
Buds are picked before they open, which in most growing areas means 2 or 3 weeks at most.
Once the weather warms the buds open within days, and the material for a bud grade is gone.
That is the same window green tea competes for, which is part of why so little yellow tea is made.
Picking happens in dry weather and after the dew has lifted, as it does for green tea.
Wet buds are worse here than anywhere, because the whole process depends on controlled moisture.
Leaf reaches the factory the same day, since damping has to begin while it is still fresh.
Some producers pick slightly later for a bud plus one leaf standard, which changes the tea.
Everything after that is a matter of hours rather than weeks, and those hours decide the result.
A narrow window and a fast process are the two facts behind the price of yellow tea.