Tea and Caffeine

Caffeine is a natural component of tea and is generally considered safe when consumed in moderation.  The way that caffeine is absorbed into the body from coffee versus tea is different.  When we drink coffee, the caffeine instantly goes into our circulatory system, jolting us to wakefulness, increasing our pulse and therefore causing our blood to pump more vigorously around our bodies [1].  However, when we drink tea, the caffeine is released much more slowly and can take up to 15 to 20 minutes to be absorbed.  With this slower absorption, the caffeine moves more gently into our central nervous system and helps to heighten our senses and increase our wakefulness.  The effects of caffeine in tea are felt more slowly, stay with us longer and go away more gradually than with coffee, rendering tea a much more efficient “pick-me-up”.

A serving of tea usually contains less than half the caffeine of coffee (or 40mg). The levels of caffeine in the tea depend on the specific blends (see table 1) and strength of the tea brew (amount of tea leaves used, brewing time and water temperature).  Tea bags will release more caffeine than loose leaf teas because they infuse more quickly due to the fine, dusty particles of tea that are in the teabags.

Decaffeinated Teas:

For people who do not want to take caffeine into their bodies, decaffeinated tea is available, but the quality and flavor vary tremendously depending on the decaffeination process used.  There are three methods that can be used to remove the caffeine from the tea.  The details of those processes are beyond the scope of this article, but the main points are summarized [1]: 

• Carbon dioxide is an organic solvent that is inexpensive, can easily be removed from the tea after decaffeination and is harmless in small quantities.  No chemical residue is left in the tea and the flavor and tea compounds are relatively unharmed.
• Methylene chloride is the most widely used agent to decaffeinate tea, is easily removed from the tea at the end of the process and is approved by the FDA.
• Ethyl acetate is classed as a natural element found in tea, coffee, wine and bananas and is used as flavor enhancers for ice cream, candies, cakes and perfumes.  The FDA considers it to be GRAS (Generally Regarded As Safe).  One down side is that it extracts other components along with the caffeine and is difficult to remove from the decaffeinated tea.

Decaffeinate ANY tea in your home:

There is a process that you can use at home to “decaffeinate” any tea.  While this process does not remove all of the caffeine, approximately 80-90% of the caffeine content can be removed:

• Infuse your tea leaves for 30 seconds
• Pour off that infusion
• Steep your tea as you normally would

1.  Pettigrew J and Richardson B.  The New Tea Companion.  A guide to teas throughout the world.  Screen F (Ed.) 2005.  National Trust Enterprises Ltd. London, England, pp 42-44.