Tagged: tieguanyin
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.
What Steeping Time Does to the Metals in Your Oolong
A 2025 study of 108 oolongs varied brewing time and temperature directly. Time drove leaching. Temperature did something stranger, and it was not uniform.
Five Minnan Oolong Cultivars, Told Apart by Their Chemistry
Tieguanyin can mean a specific tea plant or a broad commercial product name, so a bag labeled that way answers nothing on its own. A new metabolomics study profiles five Minnan cultivars instead, and one of them carries three aroma compounds detected in none of the other four.
Oolong's Stem Holds More Linalool and Geraniol Than Its Leaf
A 2025 tissue-level study of Tieguanyin found the stem holds more linalool, geraniol and other floral compounds than the leaf. A 2022 study found leaf processed with its stem attached finishes lower in linalool and higher in nerolidol than leaf processed alone.
The 98 Percent Tea Statistic Nobody Checked
Anxi's 2012 pesticide scandal is still summed up in one repeated number. It was never a measurement of the county's tea, and the county's own reduction figures, checked against independent fieldwork, tell a more specific story.
The Old Rule About Spring and Autumn Tea, Tested Against 266 Cups
Anxi trade wisdom credits spring Tieguanyin with the fuller cup and autumn with the better scent. A 2025 study of 266 finished teas checked the chemistry, and found the saying right about direction and nearly silent about how much a buyer should let it decide.
DNA Testing Keeps Finding Tieguanyin's Own Cousin in the Bag
Genetic and spectral tests on commercial Tieguanyin keep turning up a different, related Anxi cultivar blended in, most often Benshan, close enough in leaf and aroma to pass for its more famous cousin.
Both Tieguanyin origin legends fail the record
Tieguanyin carries two competing origin stories, a farmer's dream and a scholar's gift to an emperor. Neither has a document behind it.
A charcoal roast is a sequence of fires, rested months apart
Charcoal roasting is a sequence of separate fires, not one step, and each fire does distinct, measurable chemistry to the leaf. The practice also varies more across oolong styles than most tea copy admits.
What Mineral-Heavy Water Does to Oolong: Less Catechin, a Cloudier Cup
A 2024 study brewed the same Tieguanyin in four different waters and measured what came out. Mineral content moved the chemistry, not just the story a taster tells about it.
The Pot Is Not Neutral: What Six Teapot Materials Do to the Same Oolong
Researchers brewed one oolong in six vessels, zisha and zhuni clay, stainless steel, ceramic, glass, and plastic, then measured what actually left the leaf.
China Deleted Its 26-Year Rare-Earth Standard for Tea
In 2012, Anxi farmers were caught spraying rare-earth fertilizer to force faster growth on cheap tea. In 2017, China deleted the food-safety standard that had caught them, after concluding tea itself carries the element naturally, oolong more than any other kind.
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.
Oolong and Geographical Indication
A protected name is not a quality grade. What geographical-indication protection actually certifies for Wuyi yancha, Anxi Tieguanyin, and Phoenix Dancong.
Oolong Grades and Cultivars
Oolong carries four different things called a grade: a national sensory tier, a government cultivar registration, a trade aroma-type name, and a competition award. The canonical account of what each one actually certifies, and what it does not.
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 later defect that only resembles one.
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.
Oolong Regions and Origins
The canonical geography of oolong across its four classic origins: the Wuyi cliffs and Anxi in Fujian, the Phoenix mountains of Guangdong, and the high mountains of Taiwan, with the terroir, cultivars, and elevations that separate them.
Oolong Tea
Oolong is partly oxidized Camellia sinensis, made to a chosen point between green and black: how it is made, the major style families, how it tastes across the spectrum, and why it is brewed gongfu.