What each method actually takes
A HAND PICKER selects. They see the shoot, judge whether it is at the right stage, and take the standard they have been set — bud and one leaf, bud and two. Shoots that are not ready are left for the next round a week or two later. A MACHINE cuts. Whether it is a hand-held shear worked by two people with a collecting bag, a straddling harvester, or a self-propelled machine, it takes everything at a set height across the plucking table. That means ready shoots, unready shoots, old leaf and stem all together. The difference is selection, and it produces a difference in uniformity that runs through everything downstream.
Why uniformity matters so much
Processing applies one treatment to a whole batch. A withering schedule, a fixation temperature, a rolling pressure and an oxidation time are set for the material as a whole. If the batch is uniform, one setting suits all of it. If the batch mixes tender bud with mature leaf and stalk, no setting suits everything: the tender material is over-processed while the coarse material is under-processed, and the finished tea carries both faults. This is why fine orthodox manufacture depends on hand-picked leaf, and why machine-harvested leaf goes predominantly into CTC and into blends where consistency of the FINISHED product is achieved by blending rather than by uniformity of the input.
Machine harvesting is not simply the cheap option
TeaHQ's own reading of well-attested general knowledge, with no single source behind it.
Japan is the counter-example that matters. It is a high-wage country that mechanised its tea harvest thoroughly and produces some of the world's most exacting tea, and the reason it works is that the whole system was designed around the machine: fields laid out flat and evenly, rows shaped to the harvester, cultivars selected partly for uniform shoot emergence, and a plucking table maintained to a precision that makes a level cut sensible. Machine harvesting works badly when it is retrofitted to a field designed for hands, on a slope, with mixed seedling material that flushes unevenly. It works well when the field is engineered for it. The premium Japanese products — gyokuro, tencha — are frequently still hand-picked, and shaded fields in particular are often picked by hand.
The labour question, which is not a footnote
Hand plucking is the largest single cost in producing fine tea and it is why fine tea costs what it does. It is also the point at which the industry's labour history becomes a present-day fact rather than a historical one: the workforces that pick tea on the plantation model were assembled through recruitment systems that are documented and are not incidental to the price of the cup. Mechanisation is frequently presented as a response to rising labour costs. It is more accurately a response to labour availability — in several producing regions the younger generation does not want the work at the wage offered, and the machine is what the field gets instead of an argument about pay.
How to tell which you have
Look at the wet leaf. Hand-picked material gives intact shoots — a bud with one or two leaves attached at the stem — and a fairly consistent leaf size. Machine-harvested material gives cut edges, mixed sizes, mature leaf and lengths of stalk. A blunt cut across a leaf is a machine signature; a shoot broken cleanly at the stem is a hand one. Neither is a verdict on the tea: a well-made machine-harvested sencha is a better cup than a badly made hand-picked one. It tells you what kind of product you have and what to expect it to do.