Tea and theanine
I mentioned theanine (C7H14N2O3) in the first post of my caffeine trilogy, but I haven’t really gone into any detail about it. I suppose now is as good a time as any.
Theanine (or more precisely, L-theanine) is an amino acid found in tea, guayusa, and certain mushrooms. It acts as a relaxant, helps to improve concentration, and adds a savory (umami) flavor to whatever it’s added to. Most importantly — at least when we’re talking about tea — is what it does when combined with caffeine.
At the 2012 World Tea Expo, I attended a session entitled “Tea, Nutrition and Health: Myths and Truths for the Layman,” presented by Kyle Stewart and Neva Cochrane. They discussed the relaxation and alertness affect of tea, and also noted that a “2012 study found tea was associated with increased work performance and reduced tiredness, especially when consumed without milk or sugar.”
This caught my attention not only because of the increased work performance, but because it validated my personal preference for tea without sweetener or milk.
Stewart and Cochrane attributed the increased work performance to the combination of caffeine, theanine, theophylline, and theobromine. There have been some excellent articles on theanine, including Tony Gebely’s “Theanine: a 4000 Year Old Mind-Hack” and RateTea’s “L-Theanine and Tea.”
Both of them agree with the conclusion that theanine coupled with caffeine produces a seemingly-contradictory combination of relaxation and alertness. This isn’t news to tea aficionados, of course. People have been relaxing and focusing themselves with tea for millennia. Many of the health benefits of tea come from the caffeine, and those obviously apply to theanine-free drinks like coffee, cola, and cocoa.
Caffeine by itself doesn’t work quite the same way, however.
The “spike & crash” affect of caffeine is well known to any coffee drinker. You’re droopy and tired, you have your morning cup, and you swiftly find yourself wide awake and full of energy. A while later, bam! You’re back where you started, and possibly in a pissier mood than when you started. Yes, I said “pissier.” It’s a technical term. When drinking tea, thanks in large part to the theanine content, the effects take longer to kick in, and also take longer to wear off. Mixing a relaxant (theanine) with a stimulant (caffeine) works quite well in this case.
Wikipedia summarizes a half-dozen studies with this statement:
“Theanine has been studied for its potential ability to reduce mental and physical stress, improve cognition, and boost mood and cognitive performance in a synergistic manner with caffeine.”
“Boost mood,” eh? As I wrote last week, there has been at least one study that indicates tea improves mood. That study, however, defined a good mood as decreased fatigue. It appears that there may be more to the mood-enhancing effects of tea than my previous post indicated!
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?