At the California Tea and Coffee Brewery, we hear “need caffeine / want black tea” regularly. Many people have been told that black tea has more caffeine by another tea place or a coffee and tea place, or just thought it worked that way. The conclusion that many have drawn is that the darker the tea – or the stronger the taste – the more caffeine. Of course, that’s a misconception for both tea and coffee, and the controversy about which tea has the most caffeine has been going on for quite awhile.
We have a short summary on our counter for anyone who would like to read it, based on various studies. However, I came across an article the other day on the great blog Cha Dao with Nigel Melican that was so thorough, I thought it would be great to share parts of it.
The first passage that stood out for me was the following:
“Three scientifically verifiable facts are:
- Caffeine level varies naturally in types of tea and levels in one type may overlap with another type
- 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%)
- For a given bush, the finer the plucking standard, the higher the caffeine level …
The above summary disregards the changes in caffeine level (albeit smaller than genetic, edaphic and climatic mediated changes) produced during tea processing.”
Mr. Melican goes into much more detail, including discussing the effects of withering and oxidation on the leaves and amount of caffeine. He also debunks the quick-decaf process that was so popular on the Internet awhile back as follows:
“Again we would have to be washing our tea for a long period – three to four minutes to achieve 80% decaffeination. While a 30-second ‘wash’ under Spiro’s rather extreme laboratory conditions (small leaf CTC tea, loose in the ‘pot’ rather than in a teabag, at constant temperature and stirred vigorously) leached 20% of caffeine rather than the 9% yielded by Hicks’s more normal steeping, neither of these scientifically conducted findings comes anywhere near the 30-second/ 80%-decaffeination claims perpetuated as an Internet Myth.”
Finally, Mr. Melican provides links to informational sites that serve to make us (or me) even more unsure of what to tell customers to feel 100% accurate:
“http://nobleharbor.com/tea/caffiene.html [sic]
This page supports the information given above – summarizes the Hicks et al paper, and in places borrows some of my own data, with a few (unimportant) errors. It debunks some of the popular caffeine myths and concludes ‘all teas have roughly similar caffeine contents, and one cannot rely on the belief that green tea has less caffeine, as asserted by many popular claims.’
http://lpi.oregonstate.edu/infocenter/phytochemicals/tea/
The Linus Pauling Institute gives a fairly inconclusive comment on the level of caffeine in tea showing data (from just 20 snapshot analyses) that the green teas they analyzed varied from 40 to 211 mg/liter, while the black teas varied from 177 to 303 mg/liter — a larger and more representative sample of the worlds [sic] teas could have would have [sic] increased these ranges and the overlap considerably. However, LPI do suggest that the popular belief of low caffeine level in White Tea is misplaced: ‘Buds and young tea leaves have been found to contain higher levels of caffeine than older leaves, suggesting that the caffeine content of some white teas may be slightly higher than that of green teas.'”
I’m thankful that “tea scientists” with the status of Nigel Melican have taken the time to talk about the subject of caffeine in tea. Whatever our beliefs, there is definitely caffeine in tea, and since we don’t carry any decaf teas, we kindly point those who don’t want any caffeine at all to the wonderful assortment of herbals we also carry.
The caffeine debate is as old, as people know, that there’s caffeine in tea (or coffee).
Truth is, that 2 major factors influence the amount of caffeine in your cup: temperature and steeping time. Studies have shown, that the hotter the water and the longer you let it steep, the more caffeine will be extracted.
The max. is mostly reached with boiling water and ten minutes steeping time. All extraction above that is not significant.
Most people will think green tea keeps them awake, because they have read about it somewhere. Never underestimate the effect of placebo :-)
Thanks for the reminders Diane. I’m confused however. If we do a short steeping of 30 seconds to 1 minute – for green tea – then according to what you’re saying, the amount of caffeine would be quite low……would’t it? Subsequent steepings would be a bit more but it does sound like that initial steeping would be great for those wanting low caffeine…..or am I looking at this wrong? Also, there is a caveat that states that there are in fact changes in caffeine levels due to processing so I don’t understand the prior statement that black and green, from the same plant, picked on the same day would be the same caffeine. The difference IS the processeing. Help me here as it doesn’t make sense.
Michelle, it was a bit confusing when Mr. Melican said below the ‘same time, same plant’ that the processing wasn’t factored in, agreed. Light roasts in coffee have less caffeine than darker roasts, and it is logical that white and green tea would retain more polyphenols and caffeine than black. The less processing, the more properties retained in the bean or leaf. My vote from everything I’ve been able to find: Green and white, in LEAF form, not infused, have more caffeine. And then Gunther’s statements come into play. Anyone have more information, I’d love to get hold of it!
What really gets to me is – how much caffeine is in the cup I’m drinking? I don’t steep for 3-4 minutes, I don’t stir the leaves. I typically steep for 30-90 seconds for green tea so it seems to me that I’m not getting that much caffeine. Certainly not the amount quoted in the article that uses different methods for assessing and small leaf CTC.
Diane, do you have the impression that many people are still not aware of the caffeine content in tea? They always mention coffee.
Hi Michelle & Ifang,
Michelle, sitting here shaking my head. That old ‘Internet Myth’ Nigel talked about said 80% of caffeine was gone in that first quick steeping…but apparently totally not true. Information continues to be so hard to pin down..for me anyway. Ifang, we serve both tea and coffee and I usually get asked this way “There’s more caffeine in coffee than in tea, right?” By dry weight, there’s more in tea, but when brewed about 1/3 to 1/2 of coffee is our answer. I think the big coffee company has securely put in people’s minds that the stronger tasting or darker the coffee, the more caffeine. Even if they don’t say so, somehow people have gotten that perception.
Nigel is a wealth of information. The thing is different black teas from different regions of the world really vary in caffeine content. For example, here in China a black tea from Wuyishan really varies in caffeine content from a Yunnan black tea. I have found some white teas that in fact contain more caffeine than some black tea.
I had a similar conversation with Norwood as well when I ordered a bunch of his latest books for my students.
From what I have been able to piece together, it is almost impossible to definitively pin down which tea has more caffeine then another. According to the gentleman I spoke to about this, the terroir, the variatel, the growing region and at what stage it was harvested all greatly impact the amount of caffeine in the tea leaf. The only thing processing does is make the inherent caffeine in the leaf more available to the sipper via the infusing process – it does not increase it.
I know from experience, that when I am cupping white teas with my students vs cupping black teas, the energy level in the class is about 50 higher with white tea cuppings, and I also feel it myself.
Therefore, Nigel’s last statement:
“Buds and young tea leaves have been found to contain higher levels of caffeine than older leaves, suggesting that the caffeine content of some white teas may be slightly higher than that of green teas.’” is to me the most accurate and consistent.