Caffeine is the chemical that gets us through those tough early mornings or late nights when we are tired but need to keep going. It is a stimulant of the central nervous system, and blocks the action of adenosine in the body to prevent drowsiness. Coffee is the most well known source of the caffeine hit, but pound for pound tea contains more caffeine than coffee. So how come tea doesn't give us that same caffeine buzz?
What is caffeine?
Caffeine is produced by both the coffee and tea plants as a defence mechanism against insects. The caffeine is highly toxic to the insects so it prevents their leaves and beans from being eaten by the insects. Conversely for humans it is not toxic but in fact adds characteristics such as acidity, astringency and bitterness to the flavour profiles of both tea and coffee. There is no universal caffeine level for either leaves or beans, it will differ from plant to plant and will be dependent on the growing conditions and the age of the leaves to determine how much caffeine is present.
Tea or Coffee
Now looking at studies on caffeine levels. The average volume in tea is around 25mg per 1g and for coffee it is 15mg per 1g. However in a brewed cup of filter coffee there is over 50mg of caffeine per 100ml and in a freshly brewed cup of tea there is only 15mg per 100ml.
This difference is easily explained by looking at the volumes of each used to actually brew 100ml. To make a cup of tea, roughly 1.5g of tea are used per 100ml, whereas for coffee 6g is used. Also, coffee beans are normally ground down into fine powders, so their rate of extraction will increase due to a smaller surface area to extract the caffeine through. The principle also applies to teas, smaller leaf teas such as those used in teabags will typically infuse more caffeine in the cup than full leaf teas. To achieve the same result with full leaf teas you need to brew for longer brew or increase the amount of leaves.
Another factor in the speed of caffeine extraction is the temperature of the water used. Caffeine is moderately soluble in water at room temperature (2g / 100ml), but very soluble in boiling water (66g / 100ml), so the higher the water temperature the faster the caffeine will infuse into your cup. For most tea and coffee this water temperature is very similar, however there is a common misconception that green and white teas contain less caffeine, but if you look at our other blog “Types of tea” you will see that they all come from the same plant thus all types of tea contain the same level of caffeine. To brew both these teas correctly you are supposed to brew them using cooler water, often as low as 60 degrees. If you tip boiling hot water over these leaves then exactly the same level of caffeine will be extracted, but, if brewed correctly, less caffeine will pass into your finished brew. Therefore reinforcing this myth
One key factor in how caffeine in tea is absorbed by the body is the presence of L-Theanine. This is an amino acid which has been found to have a relaxing effect on the brain, it has been studied for its potential ability to reduce mental and physical stress, improve cognition, and boost mood and cognitive performance. It also appears to compliment the stimulant effects of caffeine by reducing the anxiety feelings that can be produce by creating a state of relaxation without drowsiness. Those “coffee shakes” just don't happen with tea and this is the reason why. There are also theories that the L-Theanine slows the uptake of caffeine into the body and this provides a more consistent release over time. Rather than with coffee when all the caffeine hits you at once, in tea the caffeine is released slowly over time in a more controlled manner.
So as expected coffee does contain more caffeine per cup and you certainly can feel the initial buzz. However, tea still contains a reasonable amount of caffeine, but with the added L-Theanine it affects your body in a much more consistent and calmer way. There might not be that initial big buzz but there is also not the inevitable crash afterwards either.
Tea plays the long game with its stimulants effect and you could feel better too if you switch your cup of coffee to a cup of quality loose leaf tea, such as our strong and smooth Gold Standard tea.