GABA (GABA tea) (佳葉龍, jiāyèlóng)
GABA is gamma-aminobutyric acid, an inhibitory neurotransmitter of the nervous system. GABA tea — usually a Taiwanese oolong — is processed without oxygen, so GABA accumulates in the leaf; its effect is gentle and calming.
GABA is the brain's main inhibitory neurotransmitter: it damps excess neuronal excitation, aiding relaxation and sleep. Ordinary tea leaf contains little of it, but in the 1980s the Japanese researcher Tsushida discovered that if fresh leaf is held in an oxygen-free environment, its glutamic acid converts into GABA. The method was described in 1984, and the industrial technology was perfected in Taiwan, where GABA oolong became a genre of its own.
The technology works like this: harvested leaf is placed in sealed containers from which oxygen has been displaced (usually with nitrogen) and held for hours, alternating anaerobic cycles with the usual stages of oolong production. Anaerobic fermentation yields not only a high concentration of GABA but also a recognizable taste: baked fruit, prunes, the tartness of a crab apple, a warm bready note — a profile unlike any classic oolong.
Its effects deserve honest discussion: how much GABA from a cup crosses the blood–brain barrier remains an open question in science. But the experience is consistent: GABA tea drinks as soft, enveloping, and evening-friendly — the state afterward is often described as a "warm blanket," a fine example of a quiet, unobtrusive cha qi. A practical tip: don't steep GABA oolong too long in boiling water — its tangy notes are easily scorched; short infusions in a gaiwan reveal it best.
Teas where this appears
Chinese tea glossary