Thursday, January 24, 2008

How much caffeine is in tea?

How appropriate of the timing to talk about caffeine at this hour?! I am wide awake at the moment from 5 teas I had earlier today. I am tired but can't fall asleep.

So how much caffeine is there in tea? I have seen lots articles comparing coffee and tea. Many of my customers told me they can't drink black tea because it keeps them up, so they want to switch to green tea. The usual question starts: how much caffeine is in tea? Tea has less caffeine than coffee right? Does black tea have more caffeine than green? Does white tea have the most caffeine?

Any of the comparing pairs are like apple to orange, kiwi to bok choi, bamboo to aloe vera, just pick any 2 strange things you can think of.

The caffeine level in any tea has little to do with the type of tea. As a tea leaf from a tea tree, the caffeine level is determined by the varietal and the soil it is in. For example, a TGY bush grows in Anxi might have different caffeine content from a same TGY varietal grows in Wuyi. A Huang Zhi Xiang varietal has more caffeine than Yu Lan Xiang varietal on the same hill. An old bush has more caffeine than its young clone. Lao Ban Zhang has more caffeine than a Yiwu. The difference is by varietals, not by type. Not all green teas have more caffeine than black, not all oolongs have less caffeine than white.

Caffeine level can vary from 2.5% to 6.5% before processing. This holds true across the board from white to black. From a leaf on a tree to consumption ready, caffeine level will change by processing and storage. Unless scientists take lab samples of every single varietal on earth for research, and farmer/sellers post that information on a label, we can not say how much caffeine does one tea contain. Even if that's done, chemicals of the trees will change as they grow. It's irresponsible to say green tea has so and so much caffeine as a whole category as seen in a million article online and in magazines. There is no definite formula for tea, it's not science like pharmaceutical drugs.

Impact of caffeine can vary from person to person also. While one person will stay up till dawn, the same tea will put an other person to deep sleep. I have heard caffeine will make people with ADD tired and sleepy. Drinking tons of low caffeine level teas will keep you up more than drinking a little bit of the high caffeine level tea. 20 tea bags to make one pot of tea will send me through the roof for sure.

I advice my clients to take small amount at the beginning and recommend teas according to their previous tea experience.


Michel said...

Imen, from the little knowlege I have read on teanerd and the french blog tetsubin (he's a pharmacist and herborist) in tea the caffeine is released gradually over time. That's why monks like it; this happens because tea has other chemical substances that act as a slow release receptical, in other words these substances are caffeine carriers.
I drink 20 g a day with no loss of sleep but red tea, even Dardgeling makes me queezy, I think it is because these teas have a lower amount of these substances therefore the caffeine is released too quickly.

Some wild teas also can keep me awake but I think it is the caffeine and the strong chi combination that does it.

Imen said...


Thanks for sharing. It makes sense that aged pu and black teas have faster (not necessary more) effects than some green teas. Because the carriers are broken down at the time of consumption. :)

Nada said...

hi imen,

i'm not sure I understand what you mean when you say the carriers are broken down at the time of consumption. Why would this differ between green/black teas?

sorry for my slowness!


Imen said...


Any extended processing: such as fermentation (in case of black tea or cooked pu-erh, roasting and post fermentation (in case of aged pu-er) will change the chemical composition in a tea leaf, hence caffeine become easier to absorb in digest system, and travels faster in blood stream. So theoretically we can feel its impact quicker/stronger. However the impact varies by person to person depending on the person's body chemical composition.

Kat said...

Then teas that claim to be caffeine free or decaffeinated are wrong?
I have begun to work at Teaopia, which is a Canadian chain of tea stores. There' are quite a few of our teas which I have been told are in this category of decaffeinated/caffeine free. In addition I have also been told that adding water at 80 degrees for a mere 30 seconds and discarding the liquor prior to steeping will lower the amount of caffeine.
From my own experiences I have found that, you state, all teas effect everyone differently. Even if the label states otherwise.

A friend of mine who had hormone level problems has decided to stay away from Green Tea because of it's high amount of caffeine which, according to her source, lowers the amount of Estrogen in her body.

In my personal opinion, tea should be drank relentless of what it may do to our bodies. Unless you know what effect the tea may or may not have on you, enjoy <3

What is your opinion?

ahnn said...

Green tea has more caffeine but the caffeine can be beneficial for the body because contain a chemical that helps that caffeine to be useful for the body.

Jay0646 said...

There is a group called ZEST Tea raising funds on RocketHub right now that is making a caffeine enriched tea. They claim the tea has as much caffeine as coffee. I bought myself a box and am interested to see how it turns out.

Found it here: