Theogallin
A minor acid that contributes to mouthfulness — the sense that a liquor has substance rather than merely strength.
What a drinker notices
- Body and texture — a tactile sensation
- Sourness — a taste
Fullness and continuity in the mouth, with a faint acidity underneath. On its own it is barely identifiable; taken away, a liquor reads thinner without any single taste having gone.
What this gets credited for, wrongly
Body in green tea is usually credited to total dissolved solids or to leaf quantity. Concentration is real; so is a small group of low-threshold compounds of which this is one, and adding more leaf does not substitute for them.
What it is
Theogallin is one of the compounds behind a quality tasters describe and chemistry has struggled to locate: mouthfulness, or the impression that a liquor has body and continuity rather than being a thin solution of tastes. It is a small contributor by weight and it is characteristic of tea, which makes it useful for describing what separates a good green tea from a merely strong one. Its presence is a reminder that the compounds shaping a cup are not only the abundant ones — a low-threshold minor constituent can matter more than a major one.
Chemically: Phenolic acid — gallic acid bound to quinic acid, close to specific to tea.
Where it occurs in the plant
Present throughout the shoot at modest level, higher in young leaf, and among the compounds that fall as leaf matures.
What processing does to it
In tea, processing is not a modifier applied to a fixed composition — it is what decides the composition. These are the steps that move this compound, and each links to the step itself.
- Kill-green (fixation) — Locks it in place
- Preserved by early fixation along with the rest of the fresh-leaf profile, which is part of why green tea carries this quality more distinctly than oxidised tea does.
- Oxidation — Lowers it
- Falls during oxidation as the phenolic pool is rearranged, so its contribution to body in a black tea is small relative to the thearubigins.
How brewing brings it out
Extraction rate: Fast — among the first things out of the leaf
Soluble and early, present even in a cool brew. Cold-brewed green tea keeps a surprising amount of body for its low catechin extraction, and this group is part of the reason.
Across infusions: Early and quickly spent, so it belongs to the opening cup of a session rather than to the middle of it.
Water: Behaves as the other small acids do — its contribution to briskness is dulled by alkaline water and preserved by soft, low-bicarbonate water.
What you can change
- Present at almost any temperature; extraction is not the lever
- Choose young-leaf tea if body without astringency is what you want
Teas this compound defines
Read next
- Gallic acid — The gallate group after it has been separated from its catechin — small, sour, drying, and a marker of how far a dark tea has fermented.
- Free amino acids — The savoury half of the balance that decides whether a green tea tastes sweet or brisk — and half of the ratio Chinese graders actually use.
- Pectins — The cell-wall polysaccharides behind thickness and slipperiness — the quality Chinese tasters call hou and English-language tasting notes struggle to name.
What this page does not say
This record describes a minor compound's contribution to the texture of a liquor. It makes no statement about what it does in a body.
Sources
- TeaHQ editorial synthesis — TeaHQ
This page is TeaHQ’s own synthesis of well-established tea chemistry. No external technical document stands behind it, and that constraint is why there are almost no numbers here: directions, rankings and mechanisms are stated plainly, quantities are not, because a figure nobody can check would look more authoritative than it deserves.