Shading

What it is

Shading is the one production step that happens in the field rather than the factory. Reed screens, cloth or synthetic netting are placed over the bushes for anywhere from a week to a month before harvest, cutting light dramatically. The plant responds by producing more of the amino acids associated with savoury depth and less of the compounds associated with astringency, and the leaf darkens to a deep green. It is labour-intensive, reduces yield and stresses the bush, which is why shaded teas cost several times what unshaded ones do.

Also transliterated as: hifuku saibai, kabuse.

What it does to the leaf

Restricts light to the growing leaf, shifting its amino-acid and polyphenol balance and deepening its colour before harvest.

What it does to the cup

Pushes the cup towards thick, sweet, savoury and low-astringency character; reduces the grassy sharpness of an unshaded leaf.

Variants that matter

Ways this step is carried out that produce genuinely different results, rather than regional names for the same thing.

Kabuse (light shading)

Roughly one to two weeks, giving kabusecha — a middle point between sencha and gyokuro in both character and price.

Full shading (gyokuro and tencha)

Three weeks or more under progressively heavier cover. Produces gyokuro when rolled, and tencha — the material for matcha — when left unrolled.

Other steps at the Plucking stage

• Fresh-leaf reception and grading — 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.
• Fresh-leaf transport and holding — 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.
• Hand plucking — Picking each shoot individually by hand, which is the only method that can choose what to take and what to leave.
• Leaf separation by hand (ban pian) — Breaking each freshly picked shoot apart by hand so that the individual leaves go forward and the bud and the stem are set aside.
• Mechanical harvesting — Cutting the top of the plucking table with a powered blade, which takes everything at a set height regardless of what is ready.
• Plucking standard — 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.

Teas that go through this step

• Gyokuro
• Karigane
• Matcha
• Matcha koicha grade
• Matcha usucha grade
• Tencha
• Yame gyokuro

Guides covering this step

• Why green tea tastes grassy — Because the fixation step preserves compounds that oxidation would otherwise transform — and because in Japanese tea, steaming preserves a different set of them than pan-firing does.
• Exploring Japanese tea styles — Almost entirely green tea, almost entirely steamed, and organised around three variables: how long the leaf was steamed, whether the bushes were shaded, and which part of the plant you are drinking.
• Shade, and the two completely unrelated reasons it is used — Japanese producers shade tea for a few weeks before harvest to change what is inside the leaf. Agroforestry systems shade tea permanently to change the environment the plant lives in. The two practices share a word and almost nothing else.
• Amino acids and theanine: the umami and sweetness side of the leaf — The savoury, brothy, sweet quality of a fine green tea comes from the leaf’s free amino acids, of which theanine is the most abundant. Their level relative to the polyphenols is the single most useful chemical fact for understanding why shaded teas taste as they do.
• What shading does to a tea bush, and why it changes the chemistry — Covering a tea field for the weeks before picking is one of the few agricultural interventions in tea with a direct, well-understood chemical purpose. It is also expensive, labour-intensive and hard on the plant, which is why shaded teas cost what they do.
• Fertiliser and nitrogen in tea growing — Tea is harvested as new shoots, over and over, all season. That makes it unusually hungry for nitrogen, and nitrogen is where most of a tea field’s environmental accounting sits — in the soil, in the water and in the atmosphere.
• Uji, shading, and the origin of the Japanese green profile — One district acquired a technique that changes the leaf chemically, and the whole prestige structure of Japanese tea was built on it. The accident story attached to the discovery is a legend; the agronomic and commercial logic behind the technique is not.
• What matcha should cost, and what you are paying for — Matcha spans roughly two orders of magnitude in price, and almost all of the difference is decided before the leaf reaches the mill. Here is where each cost sits, and which of them a drinker can actually taste.
• What tea needs to grow — Four requirements put commercial tea where it is: warmth without hard frost, high and well-distributed rainfall, acidic well-drained soil, and enough labour to pick it. The fourth constrains the map more than the first three.