by kate on November 24th, 2011
We receive many queries about tea and its caffeine content. Unfortunately for the curious tea-drinker, there are innumerable myths circulating regarding tea and caffeine, usually propagated in internet forums. Nigel Melican, one of the world’s foremost tea experts, has written the definitive article on tea and caffeine, and we have summarised the main points below.
There are many factors that affect the caffeine content in tea, and they are not dependent solely on the type of tea
Caffeine content in tea varies according to growing environment, processing methods, season, and even which specific bush the tea is picked from, therefore caffeine levels vary naturally within every type of tea and levels in different types can overlap. For example, black tea and green tea made from the same leaf from the same bushes on the same day will have virtually the same caffeine level.
White tea is not caffeine-free
Many people beleive that white tea is caffeine-free. This is simply not true. All tea (from the Cameilia Sinensis family) contains caffeine. Furthermore, tea made of buds and leaf tips (such as White Silver Needle Tea) contains higher levels of caffeine than a leaf-only tea such as Pouchong Green Tea (but this does not mean that all white tea is higher in caffeine than all green tea).
There are some generalisations we can make about caffeine levels in different types of tea, but they are not rules
Whilst there is no such thing as a typical caffeine content for each type of tea, on the whole white tea will have a slightly higher caffeine content than green tea, and black tea will have a slightly higher caffeine content than white tea. But these are not binding rules.
As Nigel Melican proves in his article, caffeine content in tea varies due to so many different factors that any caffeine percentage given for a type of tea can only ever be accurate to one snapshot point in time. Furthermore, information about every single factor that affects caffeine levels is not available to the tea producer and the seller, making accurate caffeine level statements nigh on impossible.
You cannot decaffinate tea by washing it in hot water for 30 seconds
A popular internet myth states that you can rid tea of 80% of its caffeine by rinsing it with hot water for 30 seconds. Whilst decaffination can be achieved by washing tea, a 1996 study showed that to remove 80% of the caffeine you would have to wash your tea for at least 8 minutes, in the process draining it of any flavour it may have had. Therefore, a 30 second wash would leave at least 90% of the caffeine remaining.
Tea contains another physiologically active compound: theanine
Theanine is an amino-acid that has a calming effect on the mind. Nigel Melican suspects that the presence of this compound means that the body reacts more gently to the caffeine in tea than the caffeine in coffee. In addition, the caffeine in tea binds with tea polyphenols when it is steeping. This is a natural complexing process that results in a slower and more gentle uptake into the stomach and the brain. This is why, generally speaking, most people experience less of a caffeine ‘rush’ from tea than from coffee.
A note: All tea contains caffeine
All tea that is derived from the Camelia Sinensis plant, or a varietal of it, will contain caffeine. Only herbal tissanes (e.g. peppermint, chamomile) that are derived from other species of plant may be classed as naturally caffeine free (although they are often referred to as ‘herbal tea’). All decaffeinated teas (be they hot water washed or solvent extracted) have some caffeine remaining.
To read Nigel Melican’s full article, click here