How tea becomes tea

Processing

White, green, oolong, black and pu-erh all start from the same plant. Here is the actual sequence of decisions that turns it into five different categories.

FL-01

The five steps

01 Withering Leaf loses 30–70% of its moisture over hours, going limp enough to handle without shattering.

02 Rolling / bruising Ruptures the leaf's cell walls, releasing the enzymes and juices that oxidation depends on. Skipped entirely for white tea.

03 Oxidation Bruised leaf is spread out and left exposed to oxygen — minutes for a light oolong, hours for black tea. Skipped for green tea.

04 Fixing (kill-green) Heat deactivates the enzyme driving oxidation. For green tea this happens first, before any oxidation can start; for oolong and black it happens last, to lock in the level already reached.

05 Firing / drying Final moisture is driven down to roughly 2–5%, low enough for the leaf to store for months without spoiling.

FL-02

Oxidation spectrum

Every type below is the same plant, carried through the five steps above in a different order or stopped at a different point. Pu-erh isn't on this axis at all — see the note beneath it.

Green 0%

Heat-fixed within hours of plucking — steamed in Japan, pan-fired in China — so oxidation never starts.

White 0–2%

No kill-green step at all: just withered and dried, so a trace of natural oxidation happens on its own.

Oolong 8–80%

The widest range of any type by design — a light Anxi Tieguanyin and a dark Wuyi rock oolong are both "oolong".

Black 95–100%

Rolled hard to rupture the leaf, then left to oxidize fully before firing locks the colour in.

Pu-erh

Raw (sheng) pu-erh is sun-dried and aged slowly over years; ripe (shou) pu-erh is put through an accelerated microbial pile-fermentation. Neither is the enzymatic oxidation this chart measures, so it isn't placed on it.