Tea Blog

It’s a bit of a paradox that a drink containing caffeine can also produce a sense of calm and relaxation. Tea is often cited as an example of this effect, largely due to the presence of theanine. As discussed in this overview of theanine and its role in tea’s calming properties, theanine is an amino acid found almost exclusively in the tea plant and was first isolated by Japanese researchers in 1949.

Complicating matters slightly is the presence of another term often associated with tea: theine. While less commonly discussed today, Oxford Dictionaries defines theine as simply caffeine when it occurs in tea. See this definition of theine as a historical term for caffeine in tea for additional context.

Although theanine was not identified until the mid-twentieth century, references to theine date back much further. For example, this nineteenth-century scientific text discussing the presence of theine in tea includes early observations about its chemical properties, even if the understanding at the time was limited.

In another early scientific discussion, this 1873 article from The Chemical News examining theine content in different types of tea suggested that black tea might contain higher levels than green tea. While modern research presents a more nuanced picture, the idea still echoes in common assumptions about caffeine content.

Finally, historical perspectives on tea and caffeine often included claims that do not align with current understanding. For instance, this nineteenth-century medical journal article discussing the effects of tea temperature on caffeine suggested that chilling tea could reduce its stimulating properties. Such claims, while interesting, should be viewed with a degree of skepticism given modern research.

See more of William I. Lengeman’s articles in this archive of tea-related writing by the author.

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