The caffeine content of different types of tea, such as green tea, white tea, oolong or black tea, is something that many people seem to be curious about, whether they approach tea as a health promoting beverage And they worry about drinking too much caffeine, I find it difficult to stay awake at work and I wonder if it could offer me some encouragement, or just want to have tea in the late afternoon while I go to bed at a respectable time. This has led to a market for decaffeinated tea, naturally caffeine-free “tea,” and has led to the enactment of a myth as fact.
Tea (camellia sinensis), like coffee and cocoa, contains caffeine. Green tea, oolong tea, black tea, and white tea come from this plant or a sub-variety of it and therefore share that common trait. Any tea that does not contain caffeine is not actually tea or has been processed with one of several solvents to remove the caffeine.
This presents another problem; Many people choose to drink tea, particularly green tea, due to its rich content of antioxidant polyphenols, but the most common method of decaffeination with ethyl acetate as a solvent generally removes 82% of the polyphenols along with the caffeine.
As a result, several people, in an act of desperation, have come up with the idea that by washing tea leaves in boiling water for 45 seconds and discarding that wash, then preparing the leaves again for drinking, 80% of the tea could be removed. mixture. caffeine without robbing the tea of its super happy and healthy goodness. Sorry, friends and neighbors, but this is simply not true.
While there is no scientific evidence to support this claim, there are several studies that deny it. A 1996 study entitled ‘Tea preparation and its influence on methylxanthine concentration’ (1), used 6 varieties of tea (3 bagged, 3 loose, including oolong, green tea and black tea varieties) and found that after five minutes of soaking, an average of 69% of the caffeine present in the dried leaf had reached the water. Another 2008 study by the Faculty of Science at Mae Fah Luang University in Chiang Rai, Thailand, produced similar data with samples of Thai green tea and oolong. (2)
Where does that leave the person who wants to drink tea, but doesn’t like caffeine too much? The answer is apparently as simple and beautiful as tea leaves ……… L-theanine. L-Theanine is a non-protein amino acid found only in tea plants. In fact, it works antagonistically against the effects of caffeine by directly stimulating the production of alpha waves in the brain, creating a deep sense of relaxation and alertness physiologically similar to that achieved through meditation. It is also involved in the formation of the inhibitory neurotransmitter, gamma amino butyric acid (or GABA), which influences two other neurotransmitters that we all know and love, dopamine and serotonin.
Together in tea, caffeine and theanine dance in such a way that leaves you feeling energized and (counter intuitively) relaxed and at peace, without threatening to give you the wild caffeine hangover that coffee or soda can.
1) Quoted from International Food Research Vol 29, Nos. 3-4, pp. 325-330
2) Caffeine in Chiang Rai Tea Infusions: Effects of Tea Variety, Type, Leaf Shape, and Infusion Conditions.