We’ve all heard it: Green tea doesn’t have much caffeine. Black tea has lots more.

But, the more I learned about tea and how the different kinds of tea are made, the more I wondered about one simple question: How does oxidizing a tea leaf, changing it from green to black, actually add caffeine? Where does the extra caffeine come from?

Answer: It doesn’t.

The Truth

After reading the second main point of this Cha Dao blog post, it made sense. The short version: Scientific study has proven that “Black and green tea manufactured from leaf from the same bushes on the same day will have virtually the same caffeine levels (within +/- 0.3%)” (emphasis mine).

In other words, the little info graphic on the back of the box of tea I bought at a grocery store last year, explaining the different caffeine levels of white, green and black tea, is a lie. Or, to quote the author of the blog post, “is so wrong as to verge on the fraudulent.”

Caffeine Levels in Coffee

So where do different levels of caffeine come from? I suddenly remembered other studies I had seen, where scientists measured the real-life caffeine levels of coffee from different restaurants and coffee shops. Result? The caffeine levels per 8-ounce cup of regular coffee were all over the map.

Caffeine is a naturally occurring substance in a number of plants that *acts as an insecticide. And, as with many things in nature, the exact quantity varies considerably from one leaf to another. Or, in the case of coffee, from one bean to another. (Well, actually, from one seed to another. Coffee “beans” aren’t beans.)

For some fascinating discussion on what factors affect the caffeine level of tea leaves, read the rest of that blog post. There are some recognizable patterns that make it somewhat possible to predict general caffeine levels.


As I researched this question, my wife seemed amused by the whole topic. “Why do you Americans care about these things?” she asked. She pointed out that Chinese people don’t care how many milligrams of caffeine are in their cup, and whether or not it matches the number of milligrams in somebody else’s cup.

She made me realize that we Americans are obsessed with quantifying everything, including the unquantifiable. When nature doesn’t fit our goal of standardizing everything into perfectly uniform boxes, we get annoyed and frustrated and wonder what went wrong.

Why do we do it? I think because we want to max everything out. If we know the exact milligram count, we can flirt with excess without crossing a scientifically-defined line. But if we absolutely must have an accurate milligram count to tell us if we’re being intemperate with our temperance beverages, then we’re probably already intemperate. [Oops! Guilty!]

So, the moral of the story for my fellow Americans is: just chill. Life is messy. Enjoy it in moderation.

And don’t say “No” to black tea because you think it has more caffeine than green.

Unfortunately, I came across the Cha Dao post after I ordered a pound of Earl Grey Green instead of traditional black. I thought I was being a good boy and limiting my caffeine intake. Although the green is actually pretty good, I can assure you that my next order will be black!

* Thanks to Erik Hansen for pointing out the linked source on caffeine’s function.

Featured Image: Elijah Wilcott, 2016