Sheng vs. Shou: Caffeine Content?
Is there a appreciable caffeine difference between these two types of puerh?
Does pile fermentation have an effect on caffeine content?
A lot of people say that shou has less caffiene than sheng, but the only measurement I know of is in the book Tea: History Terroirs Varieties and the puerh teas were right in the middle of the ballpark: the two shengs had 23 and 22 mg/500 ml while the two shous had 23 and 19 mg/500 ml.
For comparison, matcha had 126 mg/100 ml, oolongs ranged from 12 to 49 mg/ml, and the Darjeeling was 16 mg/ml. BTW: it’s a great book; I highly recommend it.
Tricky. It seems to me that those numbers, even if they are correct, are only useful for a relative comparison. Certainly if the brewing parameters are unknown. In other words they aren’t much help in figuring out how much caffeine one is actually consuming, unless you know the parameters they used and then brew it exactly the same way (which you won’t if you gongfu the tea with multiple steeps).
It seems reasonable to assume that the extraction of caffeine from the tea is not linear, so even if the parameters are known, translating them to different parameters most likely won’t work (i.e. if you double the steeping time you probably won’t get twice the caffeine).
Thanks Dr Jim!
I see the mg/volume are different for the non-puerh teas. Should I covert the others to mg/500 ml?
For example:
- matcha = 630 mg/500 ml.
I left out some of the details. The table was labeled: “All teas were infused in a teapot and 2 cups (500 ml) water, except matcha sendo, which was whisked in a bowl with a scant 1/2 cup (100 ml) water.” All teas were 5 gram samples, except for the Matcha, which was 1.5 g, which means that the ratio of tea to water was relatively close for the match (multiply by 4 to get 6 grams per 2 cups). Don’t ask me about the 2 cups = 500 ml, while 1/2 cup = 100 ml. I’m just reading what they wrote.
Looking more carefully, the steep times and water temperatures also varied. One of the shengs had a 6 minute steep time; the other 3 puerhs were all 4.5 minute. Definitely not gong-fu. All were at 203F (95C). Bottom line is that the answer to your original question is that shou and sheng have the same caffeine to within the (potentially significant) variability of the small sample size.
FYI: The book also debunks the theory that you can steep a tea for a minute, throw out the liquid, and then have decaffeinated tea. In fact, in two three-minute steeps, the second steep with have more than half as much caffeine as the first.
I do not think you can generalize and say that shou has less or more caffeine than sheng. I do know that the composition of the tea effects the caffeine. Buds are highest in caffeine, followed by small leaves and then large leaves. Stems have even less caffeine and tea flowers have the least caffeine. It seems to me if you find a ripe without many buds and primarily large leaves it will have less caffeine. A brick that contains a lot of stems even less so. I do not remember where I got this information but I believe the basics of it to be true.
There are very few companies who test their teas for caffeine content. It was mentioned that Teavivre did so and I know that Teavana tells you the approximate caffeine range of all of their teas. It is too bad they don’t have better teas because I like the fact that they tell me the caffeine content. I wish Yunnan Sourcing would start testing their teas for caffeine content when they test them for pesticides.
It would be interesting to find out if the fermentation process had an effect on the caffeine content. The way that the Japanese roast their Hojicha lowers the caffeine I do know that.
The biggest myth about caffeine is that you can steep a tea for 30 seconds, throw out that tea and resteep it and you will have decaf. That has been scientifically proven false although I do not have a link to the study. It turns out you would have to steep your tea for something like fifteen minutes to effectively decaffeinate it. I don’t think a resteep after that would taste like much.
I did once see a decaf puerh offered on EBay but I am pretty sure they were lying. I have often wished there was such a thing and once asked Scott from Yunnan Sourcing about it. He decided to look into it and he found that if there was any such thing he couldn’t find it. For some reason it is almost always black tea that is decaffeinated.
I think the reason there is no such thing as decaf puerh is the Chinese don’t worry much about caffeine, that is a western thing. I do not believe any decaf is made for the Chinese tea market.
Not so much a western thing as an American thing. It’s really hard to find decaf coffee in Europe. Starbucks is about the only sure bet, and even then they aren’t used to being asked (they screwed up my order).
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