GABA Tea
GABA tea is tea processed in an oxygen-free atmosphere, usually nitrogen, so the leaf builds up gamma-aminobutyric acid; most is sold as oolong from Taiwan or Japan.
Definition
GABA tea takes its name from gamma-aminobutyric acid, an amino acid that tea leaves produce from glutamic acid when they are starved of oxygen. Researchers in Japan developed the method in the 1980s: fresh leaves are sealed in tanks and held in nitrogen or under vacuum for several hours before normal processing. A Japanese benchmark often cited for the label is at least 150 mg of GABA per 100 g of dry tea, many times the level in ordinary tea. The anaerobic step can be combined with any processing style, so GABA green tea, GABA black tea and GABA oolong all exist. In practice most GABA tea on the market is oolong from Taiwan, where producers adopted the method in the 1990s, often with a medium roast. Some processors repeat the anaerobic step several times to raise GABA content further. GABA tea is sold mainly on health claims about relaxation and blood pressure. The evidence for those claims in humans is limited, and the amount absorbed from a cup is uncertain, so it is better judged as a tea with its own flavor than as a supplement.
In Depth
Flavor: the anaerobic stage leaves a distinctive note, often described as fruity and sour, like dried apricot, plum or cooked fruit, sometimes with a fermented edge. Roasted GABA oolong adds caramel and cinnamon notes. Drinkers who expect a clean floral oolong are often surprised.
Brewing: brew as oolong: 90-95°C (194-203°F), 5-7 g in a 100 ml gaiwan or teapot, first steep 20-30 seconds, then lengthen. Western style, 3 g per 250 ml for 3-4 minutes. Most GABA oolong is rolled into balls and gives five or more infusions.
Buying: check whether the seller states a GABA content per 100 g and the base tea (green, oolong or black). Caffeine is not removed by the process; GABA tea has roughly the caffeine of the equivalent ordinary tea.
See Also
- Taiwanese Oolong
- Tea Chemistry