Aged GABA oolong

Where it grows

The districts recorded against this tea, all of them in Taiwan. Elevation is given as the band the district is recorded at, not a measurement of the garden this leaf came from.

• Nantou — 400–1800 metres

  How firm this is: Inferred from general knowledge of the district rather than measured or taken from a source that states it.

The plants it is made from

Cultivar is the level below the variety group: a named selection of the tea plant, propagated as clones from one parent. Most consumer writing stops at the country and the category, which leaves out the layer that decides how the leaf behaves before anyone picks it.

• Jin Xuan — Camellia sinensis var. sinensis

  Higher-yielding and considerably hardier than Qing Xin, with a soft buttery aroma. Grown at low elevation it is an ordinary everyday tea; grown high it is genuinely fine.

How it is made, in order

Read top to bottom: the list is the production sequence, and the sequence is what makes this tea its category rather than a neighbouring one. The same leaf from the same bush becomes a green tea or a black tea depending on where the heat falls relative to the bruising, so reordering these steps would not vary the tea — it would produce a different one.

1. 1. Withering — Reduces water content, softens the leaf for later handling, and permits early enzymatic and aromatic development.
2. 2. Bruising (shaking) — Ruptures cells selectively at the leaf margin, initiating localised enzymatic oxidation while the leaf centre remains unoxidised.
3. 3. Oxidation — Allows polyphenol oxidase to act on leaf polyphenols after cell rupture, converting them into the larger coloured compounds that give oxidised tea its colour and body.
4. 4. Kill-green (fixation) — Denatures polyphenol oxidase and related enzymes, arresting enzymatic oxidation.
5. 5. Cloth-ball rolling — Compresses and kneads leaf in cloth bundles repeatedly, forming dense spheres while progressively rupturing cell walls.
6. 6. Drying — Reduces residual moisture to a level at which enzymatic, microbial and oxidative change effectively stops, stabilising the leaf for storage.
7. 7. Ageing and storage — Allows slow oxidative, microbial and thermal change to continue in stored leaf, gradually converting sharp young character into darker, rounder and sweeter character.

The route it is made by

The steps above are what happens; this is the named production route they belong to, with the other teas made the same way.

• Anaerobic-held oolong — An ordinary oolong line with the air taken out of one slot. Where a maker would shake and rest the leaf through a night, this route seals it into a tank and displaces the oxygen.

  Where it is practised: Taiwanese production dominates, with the same method applied to black and green material there and elsewhere. It is factory equipment rather than workshop equipment, which is why the style is associated with larger producers.

What its chemistry turns on

Every true tea contains caffeine, catechins and amino acids, so listing them would say nothing about this one. What differs is what the processing above does to them — and that is the same list of steps, read for its chemistry instead of its craft.

The compounds that substantially decide what this tea is: GABA (gamma-aminobutyric acid).

• Withering
  • creates Geraniol
  • creates Linalool
  • creates Linalool oxides
  • creates Theasinensins
  • raises Methyl salicylate
  • raises Nerolidol
  • raises Soluble sugars
  • lowers cis-3-Hexenol
  • lowers Green-leaf volatiles
  • lowers Leaf lipids
• Bruising (shaking)
  • converts Leaf lipids
  • creates Theasinensins
  • raises Indole
  • raises Jasmine lactone
  • raises Linalool
  • raises Nerolidol
• Oxidation
  • converts Carotenoids
  • converts Catechins
  • converts ECG (epicatechin gallate)
  • converts EGC (epigallocatechin)
  • converts EGCG (epigallocatechin gallate)
  • converts Epicatechin
  • converts Linalool
  • creates Beta-damascenone
  • creates Beta-ionone
  • creates GABA (gamma-aminobutyric acid)
  • creates Linalool oxides
  • creates Tea cream
  • creates Theaflavins
  • creates Thearubigins
  • raises 2-Phenylethanol
  • raises Geraniol
  • raises Nerolidol
  • lowers Anthocyanins
  • lowers Theogallin
• Kill-green (fixation)
  • locks 2-Phenylethanol
  • locks Anthocyanins
  • locks Catechins
  • locks cis-3-Hexenol
  • locks Green-leaf volatiles
  • locks L-theanine
  • locks Leaf lipids
  • locks Methylated catechins
  • locks Theogallin
• Cloth-ball rolling
  • lowers Green-leaf volatiles
• Drying
  • creates Strecker aldehydes
  • raises Beta-damascenone
  • raises Thearubigins
• Ageing and storage
  • raises Gallic acid
  • raises Pectins
  • raises Pheophytin
  • raises Thearubigins
  • lowers Catechins
  • lowers Chlorophyll
  • lowers Tea cream

These are statements about the leaf and the cup. What any of these compounds does in a body is a different kind of question and is not answered here or on the pages linked from it.

Brewing

• Gongfu brewing (gaiwan)

  5–7 g/100 ml · 90–95 °C · 6 authored infusions

  Needs: Gaiwan

  Open in the brew assistant

• Western brewing (teapot or mug)

  1.5–2.5 g/100 ml · 90–95 °C · 2 authored infusions

  Needs: Western teapot

  Open in the brew assistant

When the cup goes wrong

Written against oolong as a category rather than against this tea in particular, and worked back from the symptom to the likely causes in order. 18 apply to the category; the first 6 are shown.

• Every infusion in my gongfu session tastes the same — The cups are pleasant and interchangeable, with none of the change from steep to steep the method is supposed to show.
• My clay pot has changed how the tea tastes — A tea that tasted right in porcelain comes out muted, differently scented, or carrying something that was not in the leaf.
• My cold brew tastes like faintly flavoured water — After a night in the fridge the jug is pale and tastes of very little, with none of the sweetness cold brewing is supposed to give.
• My first infusion is always the worst one — The opening cup is thin, dusty or flat, and the second is markedly better — consistently, across different teas.
• My gaiwan is too hot to hold — The rim and lid become uncomfortable within seconds, the pour is rushed, and tea ends up on the tray.
• My gongfu brewing falls apart when I have guests — Sessions that work perfectly alone become chaotic with three or four people: the tea is inconsistent, the pours are rushed, and the cups arrive at different strengths and temperatures.

Every diagnosed brewing problem

If you like this

Grouped by why they were suggested, strongest reason first. Nothing here is a blended score — a suggestion appears under the best reason that exists for it, and never under a weaker one as well.

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