Est. 1956 · The Order The independent guide to oolong: the partly oxidized teas, and how to brew them Oolong.biz
THE ORDER OF THE SEVENTH STEEP SEMPER PARTIM OXIDATUM OOLONGThe Order of the Seventh Steep
The Order of the Seventh Steep
OOLONG
Semper Partim Oxidatum Always partly oxidized

Tagged: kill-green

Article · Oxidation & Roast

A Camera Can Now Grade How Fermented Your Tieguanyin Is

A 2026 study taught machine-learning models to read Tieguanyin's fermentation stage from ordinary photos and hyperspectral scans, graded against a two-of-three vote among tea masters, not a chemical threshold and not one expert's word alone.

Aug 23, 2026
Article · Basics

Why one plant makes green, oolong, and black tea

Green, oolong, and black tea are the same leaf from Camellia sinensis. What separates them is processing, above all how much enzymatic oxidation the maker allows before heat arrests it.

Jul 1, 2026
Article · Health & Science

Same Leaf, Split Into Green and Black, Kept Almost the Same Caffeine

Catechins collapsed by more than ninety percent between the two halves. Caffeine barely moved. Oxidation, the reaction that defines oolong, is not what decides how much of it ends up in the leaf.

Feb 23, 2026
Guide · Oxidation & Roast

Oolong Aroma

More than 300 volatiles have been identified in oolong, and most of them were not in the fresh leaf. What the stress route, the locked glycoside pool, and the roast each contribute, and why the received account of the second one is contradicted by direct measurement.

Guide · Oxidation & Roast

Kill-Green

The heat step that arrests enzymatic oxidation in oolong. What denatures the enzymes and why it cannot be undone, the wok and the drum with their real numbers, how a maker judges it done, the two ways it fails, and the storage defect that only resembles one.

Guide · Oxidation & Roast

Oolong Oxidation and Roast

The two axes that define an oolong. What enzymatic oxidation is and how it is arrested by kill-green, why oolong sits partly oxidized between green and black, and how roasting is a separate step applied afterward.