How much caffeine does green tea contain?
Green tea
Does green tea have caffeine? In short, yes. But the important question is: How much? That’s a much harder question, because different studies have found that the caffeine content of any given cup of green tea varies.
If you were to rely entirely on Yahoo! Answers for your answer to whether green tea contains caffeine, you’d find yourself very confused indeed. Take this page, for example. First answer: “No it doesn’t.” Second and third answer: “Yes it does”.
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The truth is, green tea does contain caffeine. But if people will try to tell you that a cup of green tea contains X amount of caffeine, take it with a grain of salt. The caffeine level of any given cup of tea you drink varies based on how long you allow your tea to brew, how hot the water is and whether it’s the second (or subsequent) brewing of the same batch of tea leaves. There are also variations of caffeine content based on how the tea is produced. (For more on the factors affecting tea’s caffeine content, I can recommend The Story of Tea: A Cultural History and Drinking Guide
Given these variations, it’s impossible for most of us to know how much caffeine our tea contains. One average figure I’ve seen is that green tea contains about 20 mg of caffeine. This is half of what black tea contains and about a quarter the caffeine content of your average cup of coffee. But as I said, these are averages, and there is significant deviation from the mean.
Teya wrote on January 6th, 2009 at 5:10 pm
Loved your article about green tea and caffeine content. You are quite right in the fact that it is impossible to determine the exact amount of caffeine in our tea.
I have done a comparison of some teas and there caffeine content here:
Caffeine in Tea
Hopefully others will find this useful as well. Nice blog, I will be back to read more.
Teya
Crazy For Tea
Jo wrote on January 6th, 2009 at 6:31 pm
It’s interesting to see that the subject of caffeine levels in tea still attracts so much interest after years of discussion. I think that the Western world should just follow the example of the Chinese and not concern themselves with such trivial facts. Enjoy the tea you like and not the one you’ve read had the most favorable number in the caffeine content list (whether that’s low or high).
There’s very limited published data on the caffeine content of tea and information is often contradictory as you rightly stated. For a good discussion on the caffeine myth, have a look at Nigel’s in-depth article and ensuing discussion on Cha Dao.
There also used to be a website listing tested caffeine content of specific teas (some of these results were rather surprising and in clear contradiction to Teya’s table). Unfortunately, the website is no longer available, but a copy can be found at the web archive.
Jo
Fergus Ray Murray wrote on January 26th, 2009 at 12:10 pm
Thanks for that.
The tricky thing seems to be that most of the variation in the caffeine content of a given cup is down to how it’s brewed, not what’s in the tea to start with. Unfortunately, I haven’t found a single study that looks at the content of various different types of tea *when brewed correctly*. One study got part-way there, following manufacturer’s guidelines from the packet, but unfortunately these are themselves wildly inaccurate a lot of the time.
It seems to be the case that a cup of green tea brewed with boiling water for three minutes will have *about* the same amount of caffeine as an equivalent cup of black tea – but of course, it will also taste as rank as all hell, because that’s completely the wrong way to brew green tea!
It looks like pu erh is about the only tea which has a really radically different caffeine content to start with…
Jhen wrote on July 24th, 2009 at 9:28 pm
“I think that the Western world should just follow the example of the Chinese and not concern themselves with such trivial facts.”
I think this is akin to putting your head in the sand. If you want to do whatever you choose without considering the facts, then by all means do so, but to recommend others not concern themselves with such “trivial facts” is at once foolish and irresponsible.
I’m in my early 30’s and have SVT (look it up). Caffeine is a BIG deal to me, and I need to know such “trivial facts”. YOU follow the example of the Chinese. I’ll continue to watch my caffeine intake, enjoy a healthier heart, and sleep much, much better than I used to.
Nick wrote on August 17th, 2009 at 11:00 am
I agree with the above post. I have been having frequent headaches and only recently made sure to have my cup of tea EVERY morning. No headaches for months now.
Eric wrote on August 17th, 2009 at 6:59 pm
Interestingly enough, I had a similar experience to you Nick. Early last year I was getting migraines almost every weekend. I’d be fine during the week, but halfway through Saturday, or on Sunday morning, I’d have a migraine. Like clockwork. I figured out I wasn’t drinking a strong cup of black tea on Saturday mornings, whereas every other day of the week I did — it was like I was having withdrawal symptoms. Sure enough, once I started drinking a couple of strong cups of tea on Saturdays and Sundays, the headaches became far less frequent.
Granted, I’m not so sure it’s a good thing to have to rely on a cup of strong tea to avoid a migraine…