Understanding oxidation
One variable, walked from almost none to complete. Oxidation is the axis the whole classification rests on, and tasting it in order is the only way it stops being an abstraction.
Who this is for
Someone who has read that oxidation defines tea categories and cannot taste what it does.
What you should come away with
The ability to place an unfamiliar tea on the oxidation scale from the cup, which is most of what category identification amounts to.
Leg 1 · None, and almost none
Green tea has none by design. White tea has a little, acquired slowly during a long wither despite being described as unoxidised.
Starting point. Everything after this is measured against it.
Fuller and more interesting than Silver Needle, with a hay-and-melon sweetness and enough body to survive being brewed properly hot. The leaf does most of the work the bud cannot.
Why this step follows
More flavour per pound and far more forgiving to brew than the bud-only grade.
Quiet and sweet, with very little bite. Its subtlety is genuinely easy to miss — under-leafed or under-steeped it tastes like faintly sweet water, which is the usual reason people find it disappointing.
Leg 2 · Partial, at the light end
A change of category. Baozhong is barely oxidised and Tie Guan Yin only slightly more — the bruising step is what makes both oolongs.
Starting point. Everything after this is measured against it.
Barely oxidised and highly aromatic — almost a continuation of green tea, and the natural first step into the oolong category.
Why this step follows
From the lightest strip-rolled oolong to the lightest ball-rolled one. Same low oxidation, entirely different extraction behaviour.
Vividly floral and almost green in character, with the aroma at maximum and the body correspondingly light.
Leg 3 · Partial, at the heavy end
Further along the same axis. Higher oxidation and real roast, and the point where oolong starts resembling black tea.
Starting point. Everything after this is measured against it.
Baked fruit and caramel over the familiar rolled-oolong base, with far more warmth than the modern light style.
Why this step follows
Both roasted Taiwanese oolongs, one moderate and one taken to the edge. The step up is in roast depth rather than in oxidation.
Deeply roasted without being charred, which is the whole difficulty of the technique. Poor examples taste of nothing but burnt sugar.
Leg 4 · Complete
The end of the scale. Full oxidation, and the malt and astringency that come with it.
Starting point. Everything after this is measured against it.
Strong and straightforwardly malty, engineered so that milk and a short steep produce the same cup every morning. Judged as a single origin it is unremarkable; judged as a blend it is a piece of consistent engineering.
Why this step follows
The blend’s dominant component, on its own. The first useful step out of blends is usually meeting one of their parts.
Thick and malty with a firm astringent grip. The second flush is the one worth seeking: it carries a rounder, almost stewed-fruit sweetness under the malt that the first flush has not yet developed.
Read alongside
- How processing changes flavour
One species, six categories, and the whole difference is a sequence of decisions about heat, damage and time. This is the single idea that makes the rest of tea legible.
- Understanding tea categories
Six categories from one plant, separated by processing rather than by botany, colour or strength. This is the single organising idea that makes the rest of tea navigable.