How much caffeine is in my tea?
I wish there was a simple answer to this question. It would be ever so cool if I could just say, “black tea has 45 mg of caffeine per 8-ounce cup.” In fact, a number of people say it is that simple. This graph came from the front page of the eZenTea website:
And this one just showed up in my Twitter feed from SanctuaryT (the tweet said, “Finally, the truth about
#tea and #caffeine!”):
They make it pretty simple, right? But that’s not very useful when they disagree with each other! The first chart shows the caffeine green tea at 20 mg/cup and white tea at 10 mg/cup, showing that white tea has half as much caffeine as green tea. The second chart shows green tea at 25 mg/cup and white tea at 28 mg/cup, indicating that white tea has 12% more caffeine.
Then we get confusing (and frankly pretty silly) charts like this one from HellaWella:
All three charts have green tea in the same basic range (20-25 mg/cup), but the HellaWella chart breaks out black tea (which is 40-42 mg/cup in the other two charts) into “brewed tea” at 47 mg/cup and “brewed imported tea” at 60 mg/cup. Huh? “Imported”? HellaWella’s “about” page doesn’t say what country they’re from, but I’m going to guess from the spellings that they’re from the U.S. Sure, there are few small tea plantations in the U.S., but I would venture to guess that approximately zero percent of casual tea drinkers have ever had a domestically grown tea. In America, pretty much all tea is “imported.”
So why the discrepancies?
Because the people making these charts (a) don’t explain their methodology and/or (b) don’t understand tea.
As I explained in my three-part caffeine series (here’s part 1), green, white, oolong, black, and pu-erh tea all come from the same species of plant (Camellia sinensis), and in some cases, the same actual plant. We carry a black and a green Darjeeling tea that are picked from the same plants, but processed differently. No part of that process creates or destroys caffeine.
Let me make that clear: let’s say you pick a bunch of tea leaves on your tea farm. You divide them up into four equal piles. You turn one pile into green tea, one into white tea, one into black tea, and one into oolong tea. When you’re done, you make a cup of tea from each. Assuming you use the same water at the same temperature, use the same amount of leaf per cup, and steep them for the same time, they will all have the exact same amount of caffeine.
If that processing doesn’t change the caffeine content, what does?
- The part of the plant that’s used. Caffeine tends to be concentrated in the buds and leaf tips. A high-quality golden or white tea made from only buds will have more caffeine than a cheap tea made with the big leaves farther down the stem.
- The growing conditions. Soil, rainfall, altitude, and many other factors (collectively known as terroir) all affect how much caffeine will be in the tea leaves.
- The time of year the leaves were harvested. Tea picked from the same plants several months apart may have dramatically different amounts of caffeine.
- How long you steep the tea. The longer those leaves sit in the water, the more caffeine will be extracted into your drink.
- How much leaf you use in the cup. Use more leaves, get more caffeine.
- How big the cup is. This seems ridiculously obvious, but it’s something a lot of people miss. Anyone who went to elementary school in the United States knows that one cup = eight ounces. However, a four-cup coffee maker doesn’t make 32 ounces (8 x 4); it makes 24 ounces. They decided their coffee makers sound bigger if they use six-ounce cups.
Even if you and I measure the same amount of leaf out of the same tin of tea, your cup might have twice the caffeine of my cup, depending on how we like to fix it. Unless we both precisely followed the ISO 3103 standard for brewing the perfect cup of tea.
Unfortunately, the lab tests to assess caffeine content are expensive, so most tea shops never test their teas. On top of that, people can’t seem to agree on how to brew the tea they are testing. I read one study where every tea was brewed for five minutes in boiling water. That’s consistent, but it’s not realistic. You don’t brew a Japanese green tea that way, or you’ll have a bitter, undrinkable mess. Another, by Kevin Gascoyne, tested tea as most people drink it (e.g., black tea in boiling water, white tea in cooler water). That’s better but even still, Kevin’s way of brewing a particular tea may not be the way I do it.
UPDATE: After I wrote this post, but while it was still in the scheduling queue, a blog called The Tea Maestro put out a post about this same subject, titled “The Latest Buzz on Tea and Caffeine.” If you’re interested in caffeine and tea, I’d recommend reading it. If not, I can’t imagine why you’re reading this post!
The bottom line is that every tea is different. Very different. In fact, Kevin tested two different sencha teas and one had four times the caffeine of the other. If someone shows you a handy-dandy chart that indicates exactly how much caffeine a cup of tea has (as opposed to showing a range), it’s wrong.
While writing this blog post, I was drinking Green Rooibos from South Africa, which has no caffeine at all. It is a non-oxidized “redbush” tea that I blogged about back in 2011 (“I’ll have a green red tea, please“). I brewed this cup for 4:00 using boiling water. It’s a remarkably forgiving drink, and I’ve steeped it for as long as 10 minutes without ruining it. It’s usually good for at least two infusions.
Phong Sali 2011 Pu-erh from Laos
At World Tea Expo this year, I picked up a Laotian pu-erh (well, technically a “dark tea,” since it doesn’t come from Yunnan) from Kevin Gascoyne at Camellia Sinensis Tea House. I mentioned this in a blog post back in June, and said I’d be tasting it and writing about it “soon.” Well, since it’s a very young sheng (a.k.a. “raw”) pu-erh, I figured it wasn’t a big hurry, and “soon” ended up being October. Oh, well. Had to get all that Oktoberfest stuff out of the way first, I suppose.
Let me begin by explaining the label and the style of this tea.
That big “2011” on the label is the year that it was produced. Most pu-erh drinkers will tell you that a sheng pu-erh should be aged a minimum of five years before you drink it. I certainly won’t argue that the flavors improve and ripen as the tea ages, but in my humble opinion there’s nothing at all wrong with drinking a young sheng. I enjoyed the bit that I took off of this 357-gram beeng cha (pressed cake), but I’ll be saving most of it to drink as it matures. Will I be able to hang on another three years or more to drink the majority of it? That remains to be seen.
The words “Phong Sali” do not refer to the style of the tea, but to its origin. Phong Sali (or, more commonly, Phongsali) is the capital of Phongsali province in Laos. Technically, as I mentioned above, this tea style should be called by its generic name (“dark tea”) rather than its regional name (“pu-erh”), because it doesn’t come from the Yunnan province of China. Since the little town of Phongsali (population about 6,000) is only about 50 miles from Yunnan (which borders Phongsali province on the west and north), I think we can let that bit of terminology slide.
“Old tree” refers to the tea plants themselves. In most modern plantations, the tea is pruned to about waist height to make it easy to pick. In many older plantations, the tea has been allowed to grow into trees, which can reach heights of thirty feet or more. The particular tea trees from which this tea comes are over 100 years old.
Tasting the tea
Unwrapping the beeng cha provided my first close look at the tea. The leaves are quite large, and the cake is threaded with golden leaves that didn’t oxidize fully.
There is still enough moisture in the cake to make it fairly easy to flake off some tea from one edge. Shu pu-erh is often dried very hard, as it is “force fermented” so that it will be ready to drink earlier. Sheng pu-erh, on the other hand, needs a bit of moisture in it to continue fermenting over time. I decided to try it in a gaiwan rather than making a large cup, so that it would be easier to experiment with multiple infusions and smell/taste the tea as I went.
I used water just a bit cooler than boiling (water boils at 202°F at this altitude, and I used 195°F water for this tea), and roughly 7 or 8 grams of tea. Unscientific, I know, but I didn’t measure it. I steeped the tea for just a minute the first time, and got a delicate but flavorful cup of tea. The flavor is similar to a characteristic Chinese green tea (think dragonwell), but more woody and with a bit of spice.
The picture on the right shows the leaves, uncurled after the first steeping. They are large, supple, and fragrant.
That one-minute steep wasn’t really enough to hydrate the leaves, so I went for a second steep at 1:30 (pictured at left above). Much more flavor, but still extremely delicate compared to a fully-aged sheng pu-erh. I enjoyed a third and fourth steep, which had only minor changes in flavor, but was interrupted before I had a chance to keep going and see how it stood up to eight or ten steeps. An experiment for a quieter day, I suppose.
This tea is definitely worth enjoying a bit early, and I will definitely be coming back to it. Again, we’ll see how much survives to full maturity. I’m not very good at waiting!
Seasons of Tea
As my tea bar does more direct tea buying (as opposed to buying through distributors), I have an opportunity to taste some absolutely fascinating teas. As I tasted some estate-grown Darjeelings the other day, I was reminded of how much difference the picking time makes on the character of the tea.
The three teas on the right side of the picture above are all Darjeeling teas from the Glenburn estate. The terroir is identical. It’s the same varietal of Camellia sinensis var sinensis (the Chinese tea plant) — all FTGFOP1 clonals. They are all black teas. They were steeped for the same amount of time using the same water at the same temperature. I used the same amount of tea leaf for each cup. What’s the difference?
- The light golden tea second from left is a first-flush Darjeeling, picked on March 20th. At that time of year, the spring rains are over and the tea plants are covered with fresh young growth. The tea is very light in color, and the flavor is mild but complex with a touch of spiciness. Although all four of the teas in the picture were steeped 2-1/2 minutes, I actually prefer my first flush Darjeelings steeped for a considerably shorter time (although everyone has different opinions on that). I’m drinking a cup as I write this, and it’s just about right at a minute and a half.
- The amber cup to the right of the first-flush is a second-flush, picked in June. The drier summer climate produces a heartier cup of tea, with a flavor often described as “muscatel.” There is more body and a bit more astringency as well.
- The darkest cup of tea on the far right is called an Autumnal Darjeeling. This one was picked on November 10th. By then, the monsoons are over and the new growth on the tea plants has matured. An autumn-picked Darjeeling will be darker in color, stronger in flavor, and fuller-bodies, but without as much of the spicy notes Darjeelings are known for.
These seasonal differences account for massive differences in caffeine content as well. Early in the season, tea plants will have more caffeine concentrated in the new growth, which is what’s picked for the delicate high-end teas. The data that Kevin Gascoyne presented at World Tea Expo last year showed a 300% increase in caffeine between two pickings at different times of year in the same plantation.
Comparing Darjeeling teas can be difficult, as much of the “Darjeeling” tea on the market isn’t authentic. According to this 2007 article, the Darjeeling region produces 10,000 tonnes of tea per year, but 40,000 tonnes is sold around the world. Even if you don’t consider the local consumption, that means 3/4 of the tea sold as Darjeeling is grown somewhere else. That’s why it’s so important to buy from a trusted source.
When selecting teas, we tend to look first at the production style (black, green, white, oolong, pu-erh), and then for the origin (a Keemun black tea from China is quite different from an Assam black tea from India). As consumers, we rarely know the exact varietal of the plant or the picking season, but those factors are every bit as important to the final flavor.
I suppose the main message of this article is that you can’t judge a tea style on a single cup. You may love autumnal Darjeeling and dislike first-flush. You may enjoy a second flush from Risheehat and not the one from Singbulli.
Tea and caffeine part II: Exploding the myths
This article is the second of a three-part series.
Part I: What is caffeine?
Part II: Exploding the myths
Part III: Decaf and low-caf alternatives
It’s amazing. It seems like the more I learn about tea, the less I know — and the more I have to unlearn. Over the many years that I’ve been drinking and enjoying tea, I’ve picked up a lot of misconceptions. I’ve even been guilty of spreading a few of those. In the last couple of years, though, as I’ve been more actively studying tea, I’ve discovered the errors of my ways, and this article will serve both as an educational tool and a mea culpa for repeating things without doing my homework.
I already started the myth busting in the previous article with some discussion of decaffeination (Myth: decaf tea has no caffeine. Fact: decaf tea has had some of its caffeine removed). With no further ado, then, let’s continue the process by taking a look at a series of common myths and misconceptions about tea and caffeine, and the relevant facts for each.
You can decaffeinate tea at home with a short “wash”
I picked up this one in several books and numerous articles on the web. In its most common form, the myth says that if you add boiling water to your leaves, swish it around for a short time (most commonly 10 to 30 seconds) and then dump it, you’ve just removed most (claims range from half to 80% or more) of the caffeine.
Bruce Richardson debunked this in his article, Too Easy to be True: De-bunking the At-Home Decaffeination Myth, which appeared in the January 2009 Edition of Fresh Cup magazine. Working with a chemistry professor at Asbury College and one of his students, they determined that it took a 3-minute infusion to extract 46-70% of the caffeine from the tea leaves. You could do a 3-minute wash, I suppose, but you’d be extracting 46-70% of the flavor, too.
Kevin Gascoyne presented some of his research in a 2012 World Tea Expo seminar: A Step Toward Caffeine and Antioxidant Clarity. He used a batch of Long Jing Shi Feng (a green “Dragonwell” tea), which he steeped for varying amounts of time. He measured caffeine content of each infusion and graphed the results. At 30 seconds, a bit over 20% of the caffeine had been removed. By 3 minutes, it was around 42% (even lower than Richardson’s numbers). It was 8 minutes before 70% of the caffeine was extracted, and the graph pretty much flattened out there.
This process is roughly cumulative, so if you infuse your tea for 6 minutes, you’re getting about the same total caffeine as if you’d infused those same leaves 3 times, at 2 minutes per infusion. My favorite shu pu-erh may not have more caffeine than, say, your favorite sencha, but by the time I’ve finished off my 7th infusion — and you’ve infused your leaves once — I’ve probably consumed more caffeine than you have (although I’ve had 7 cups of tea and you’ve had 1).
Green tea has less caffeine than black tea
Pretty much every piece of research in the last decade has debunked this myth. And when I say “debunked,” I’m not saying that the opposite is true; I’m saying that different teas have different caffeine content, but the processing method has little to do with it.
For example, Kevin Gascoyne, in the seminar I mentioned above, presented a chart of the teas that he’d tested, ranked by caffeine content. Aside from the pu-erh teas clustering toward the center (we’ll look at why in a moment), the distribution of styles (white vs. green vs. oolong vs. black vs. pu-erh) was almost random. Even very similar teas had very different caffeine levels, like the Sencha Ashikubo with 48 mg of caffeine and the Sencha Isagawa with 12 mg.
As Gascoyne analyzed his data, he came to the conclusion that there’s a certain amount of caffeine in the tea leaves, and the processes of picking, crushing, steaming, pan-firing, rolling, oxidizing, fermenting, drying, and tearing neither create nor destroy caffeine (one exception to this, according to an article on RateTea, is that roasting a tea like houjicha can dramatically reduce caffeine). If a particular tea bush in Taiwan produces a very high-caffeine oolong tea, then that exact same bush would produce a very high-caffeine black or green tea.
The caffeine content depends on many things, including the varietal of bush, the type of soil, the fertilizer used (if any), the weather, the season when the leaves are picked, and maybe even the time of day. Richardson’s article says that adding nitrogen fertilizer can raise caffeine content by 10%. Gascoyne said he analyzed tea picked from the same plantation at different times of year and found dramatically different caffeine levels.
White tea has no caffeine (or very little)
This one is not only a bad generalization like the previous myth, but often completely backwards!
Another thing that affects caffeine extraction is the part of the plant you use. Caffeine is a natural insecticide. The caffeine tends to congregate in the newer growth, thus protecting the plant from bugs that might eat its tender shoots and young leaves. Richardson’s article described research results from Nigel Melican, the student doing the analysis. His caffeine percentage findings were:
Second leaf- 3.6%
Two leaves and a bud-4.2%
Since the finest white tea is often made from all buds or a bud-and-a-leaf, it will actually have significantly higher caffeine than a strong black tea made from the whole stalk or the 2nd-4th leaves.
When hydrating, you should avoid caffeinated beverages
According to Kyle Stewart and Neva Cochran in their seminar, Tea, Nutrition, and Health: Myths and Truths for the Layman, at World Tea Expo 2012, “studies show no effect on hydration with intakes up to 400 mg of caffeine/day or the equivalent of 8 cups of tea.”
The Food and Nutrition Board of the Institute of Medicine agreed. In their 2004 reference intakes for water, they state: “caffeinated beverages appear to contribute to the daily total water intake similar to that contributed by non-caffeinated beverages.”
In other words, if you want to drink six pints of water per day for health reasons, it’s perfectly fine to steep some tea leaves in that water before you drink it!
You shouldn’t drink tea with caffeine at night
Stewart and Cochran cited another study in their seminar which analyzed tea and sleep. They found that people unused to caffeine would experience longer times to fall asleep and lower sleep quality, as would people who consumed more than 400 mg of caffeine per day (around 8 cups of typical tea).
People who spread their consumption out through the day, maintaining caffeine in the system (cups at 9:00 am, 1:00 pm, 5:00 pm, and 11:00 pm) were able to sleep with little disruption.
But what if you have no tolerance for caffeine, or you need to maintain very low levels? In the third and final part of this series, we’ll explore some alternatives you might want to try.
Tea and caffeine part I: What is caffeine?
This article is the first of a three-part series.
Part I: What is caffeine?
Part II: Exploding the myths
Part III: Decaf and low-caf alternatives
In his excellent book, A History of the World in 6 Glasses, Tom Standage selected the six beverages that he felt had the greatest influence on the development of human civilization. Three of the six contain alcohol; three contain caffeine. Tea was one of the six.
Is it the caffeine that has made tea one of the most popular beverages in the world? The flavor? Its relaxing effects? I think that without caffeine, Camellia sinensis would be just another of the hundreds of plant species that taste good when you make an infusion or tisane out of it. Perhaps yerba maté would be the drink that challenged coffee for supremacy in the non-alcoholic beverage world.
“Caffeine is the world’s most popular drug”
The above quote opens a paper entitled Caffeine Content of Brewed Teas (PDF version here) by Jenna Chin and four others from the University of Florida College of Medicine. I’ll be citing that paper again in Part II of this series. Richard Lovett, in a 2005 New Scientist article, said that 90% of adults in North America consume caffeine on a daily basis.
But yes, caffeine is a drug. It is known as a stimulant, but its effects are more varied (and sometimes more subtle) than that. It can reduce fatigue, increase focus, speed up though processes, and increase coordination. It can also interact with other xanthines to produce different effects in different drinks, which is one reason coffee, tea, and chocolate all affect us differently.
Tea, for example, contains a compound called L-theanine, which can smooth out the “spike & crash” effect of caffeine in coffee and increase the caffeine’s effect on alertness. In other words, with L-theanine present, less caffeine can have a greater effect. See a great article from RateTea about L-theanine here.
Even though Part II of this series is the one that dispels myths, I really need to address a common misconception right now. First, I’m going to make sure to define my terms: for purposes of this series, “tea” refers to beverages made from the Camellia sinensis plant (the tea bush) only. I’ll refer to all other infused-leaf products as “tisanes.” Okay, now that we have that out of the way:
“All tea contains caffeine”
Yes, I said ALL tea. The study I mentioned a couple of paragraphs ago measured and compared the caffeine content of fifteen regular black, white, and green teas with three “decaffeinated” teas and two herbal teas (tisanes). With a five-minute steep time, the regular teas ranged from 25 to 61 mg of caffeine per six-ounce cups. The decaf teas ranged from 1.8 to 10 mg per six ounce cup.
That’s right. The lowest caffeine “regular” tea they tested (Twinings English Breakfast) had only 2-1/2 times the caffeine of the most potent “decaffeinated” tea (Stash Premium Green Decaf).
There are two popular ways to remove caffeine from tea. In one, the so-called “direct method,” the leaves are steamed and then rinsed in a solvent (either dichloromethane or ethyl acetate). Then they drain off the solvent and re-steam the leaves to make sure to rinse away any leftover solvent. The other process, known as the CO2 method, involves rinsing the leaves with liquid carbon dioxide at very high pressure. Both of these methods leave behind some residual caffeine.
(As a side note: I’m not a fan of either process. When I don’t want caffeine, I’d much rather drink rooibos than a decaf tea. I only have one decaf tea out of over 80 teas and 20 tisanes at my tea bar, and I’m discontinuing that one.)
This is why tea professionals need to make a strong distinction between the terms “decaffeinated” (tea that has had most of its caffeine removed) and “naturally caffeine-free” (tisanes that naturally contain no caffeine such as rooibos, honeybush, and chamomile).
“Coffee has more caffeine than tea”
Almost everyone will agree with the statement. For the most part, it is true, assuming you add some qualifiers: The average cup of fresh-brewed loose-leaf tea contains less than half the caffeine of the average cup of fresh-brewed coffee. In the seminar, Tea, Nutrition, and Health: Myths and Truths for the Layman, at World Tea Expo 2012, the studies Kyle Stewart and Neva Cochran quoted showed the plain cup of fresh-brewed coffee at 17 mg of caffeine per ounce versus the plain cup of fresh-brewed tea at 7 mg per ounce (that’s 42 mg per six-ounce cup, which agrees nicely with the numbers from the caffeine content study I quoted above).
Interestingly, though, a pound of tea leaves contains more caffeine than a pound of coffee beans. How can that be? Because you use more coffee (by weight) than tea to make a single cup, and caffeine is extracted more efficiently from ground-up beans than from chunks of tea leaf. Tea is usually not brewed as strong as coffee, either.
At another 2012 World Tea Expo seminar, A Step Toward Caffeine and Antioxidant Clarity, Kevin Gascoyne presented research he had done comparing caffeine levels in dozens of different teas (plus a tisane or two). The difference between Kevin’s work and every other study I’ve seen is that he prepared each tea as people would actually drink it. For example, the Bai Mu Dan white tea was steeped 6 minutes in 176-degree water, while the Tie Guan Yin (Iron Goddess of Mercy) oolong was steeped 1.5 minutes in 203-degree water. Matcha powder was not steeped per se, but stirred into the water and tested without filtering.
The results? Caffeine content ranged from 12mg to 58mg for the leaf teas, and 126mg for the matcha — which is higher than some coffees.
In our next installment, I’ll look at the myths regarding caffeine in tea, including what kinds of tea have the most caffeine and how you can remove the caffeine at home all by yourself — or can you?