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:
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.
If you make a carbonated white wine, it’s called a “sparkling wine,” unless you are producing it in the Champagne region of France. Then, and only then, should it be called Champagne. I say “should” because there are a number of countries that didn’t sign (or don’t honor) the treaties involved, but that’s a whole different blog post.
The same applies to beverages made from distilling blue agave cactus. If you are in the Mexican state of Jalisco — or designated portions of certain other states — you may call that beverage Tequila. Otherwise, you have made mezcal.
The theory behind these distinctions is not so much the strict corporate trademark enforcement that governs most usage of names in the U.S. It is more a question of terroir. If you were to take two cuttings from the same grape vine and plant one in Napa Valley, California and the other in the Rhine Valley of Germany, you would get different wines from the two vines. Terroir describes the effect that the soil, weather, drainage, and related geographical factors have on the resulting taste of the beverage, whether it be wine or tea.
Darjeeling tea is often called the Champagne of tea (this appellation is usually reserved for first flush Darjeeling tea, but we’ll ignore that distinction for the moment). This little factoid has little to do with the subject of the article, but does make for a marvelous segue from alcoholic beverages to teas, n’est pas?
Like Champagne and Tequila, Darjeeling refers not only to a particular style of tea, but to the origin of that tea: the Darjeeling district of West Bengal, India. Darjeeling tea is unique because of its terroir, but also because of the varietal of the tea plant that they use. Most tea grown in India comes from Camellia sinensis var assamica (the varietal native to India), but Darjeeling tea comes from Camellia sinensis var sinensis (the varietal native to China). Combining the terroir of West Bengal with the flavor of the Chinese tea plant produces the tea we’ve all come to know and love.
And, finally, we get to dark tea
Another geographically-named tea style is pu-erh (also spelled pu’er or puer), named for the town in the Yunnan province of China where the style originated. Only recently has the tea industry really started using the more generic name of “dark tea” to refer to fermented (as opposed to oxidized) teas.
There are two ways to make pu-erh: sheng and shu (also spelled shou).
SHENG (a.k.a. raw or green pu-erh) is the more prized by collectors. The tea is stored in a slightly damp humidity-controlled environment and allowed to slowly ferment. It’s generally not considered ready to drink for years after being picked. Shengs have the same vegetal flavors and aromas as a good Chinese green tea, but with very complex earthy undertones.
SHU (a.k.a. ripe or cooked or black pu-erh) gets a bacterial “kick-start” to the fermentation process, so it’s ready to drink within a matter of months instead of years. Shu pu-erh requires very little steeping time (I’ve spoken to producers that recommend as little as ten seconds), and many pu-erh drinkers start with a “wash,” where you add boiling water, swirl for a few seconds, and pour it off before doing a “real” steeping. Shu pu-er tends to be extremely earthy, with a “composty” undertone. The flavor profile is even richer and deeper than a strong black tea (often reminiscent of a good Keemun), but with very little astringency.
There are several common shapes of pu-erh cakes, including rectangular bricks, bird-nest shapes (“tuo cha”), and flat disks (“beeng cha”).
The standard size for a beeng cha (like the one pictured above, which I’ll be sampling and writing about soon) is 357 grams, although they can be found in smaller sizes as well. I’ve found several suppliers for 100g beeng chas lately, which is a more affordable alternative for someone new to dark teas or someone sampling a new variety.
Tuo chas, on the other hand, are available in a wide variety of sizes usually centered around 80-120g. Mini tuo chas have become quite common. Each is a single serving of tea, roughly 5g.
Bricks can be found in a variety of sizes as well.
Something new (to me, anyway) is the log-shaped dark tea. My wife, Kathy, and I found these at the World Tea Expo (the big annual industry trade show for tea people) a couple of weeks ago. The ones we purchased for our tea bar are logs about 3.625 kilos (8 pounds), 25 inches long by 5 inches in diameter. We’re selling a single log in its bamboo wrapping with a canvas carry tote for $99.99, but most people will be more interested in slices taken from the log.
In the picture below, Kathy and I are posing with what the tea grower calls the world’s largest log of dark tea. If it puts the size of that tea log in perspective, I am 6’5″ tall (195 cm) not counting the hat and boots. Not having a spare thousand dollars laying around, we didn’t buy that one!