Black Tea vs. Green Tea - Caffeine, Antioxidants, Health, Taste, Etc

It is a myth that black tea is always higher in caffeine than green tea.

Individual teas vary widely in their caffeine content.  Tea is nearly always much lower in caffeine than coffee.  A typical (8oz) cup of coffee contains about 95-200mg of caffeine per cup, whereas a typical cup of tea contains somewhere between 15-75mg, with most widely-available teas being in the 30-60mg range.  A few pointers:

• Black breakfast teas, like English Breakfast and Irish Breakfast are usually higher in caffeine because they are chosen for their higher caffeine content.
• Among Japanese green teas, bancha and kukicha are lower in caffeine than sencha; gyokuro is higher.  Hojicha, roasted green tea, tends to be lowest in caffeine.
• Chinese green teas are hard to generalize about, but the ones made of tips and leaf buds are often higher in caffeine.  Generic store-brand green tea is usually (not always) lower in caffeine than generic black tea.
• You can always brew your tea stronger, using more leaf (or tea bags), and longer times, to extract more caffeine into your cup.  Conversely, you can use less leaf, and shorter steeping times if you want less caffeine.
• White tea, just like green tea, is not necessarily lower in caffeine either.

I recommend testing out an individual tea before you drink it too close to bedtime, if you're concerned about its caffeine content.  Listen to your body and pay attention to how you feel after drinking it.  Don't just believe a company's claims about the caffeine levels in their teas--some companies, especially those marketing green or white teas, make misleading or false claims that their teas are low in caffeine, in order to sell more of their products.

For more detailed information and sources, visit RateTea's page on the caffeine content of tea.  The Mayo Clinic also cites figures on the caffeine content of various drinks.

Green tea has achieved widespread fame for its high levels of antioxidants.  However, it has also been heavily over-hyped, especially by companies pushing green tea supplements or extracts.

Black tea also contains antioxidants.  When tea is oxidized, in the process that turns the leaf a dark color, the antioxidants in green tea (called catechins, a type of flavan-3-ol) change chemically, becoming thearubigins, a type of tannin).  Tannins have a bad reputation, but these chemicals are antioxidants just like the catechins in green tea.  Black tea also has a potent antioxidant effect.

The levels of these chemicals varies widely from one tea to the next and it is not possible to generalize about green teas being universally more potent as antioxidants when compared to black tea.  All teas are healthy, and I recommend buying teas that are fresh and that you enjoy both in terms of flavor and how they make you feel, rather than drinking teas you don't enjoy because they are supposedly higher in antioxidant activity.

Because tastes are so intensely personal, it's not possible to say that green tea universally tastes "better" or "worse" than black tea.  But I have tried dozens of both types of teas, and I can't even generalize about the broad classes of tea--I like some green teas and dislike others, and the same goes for black tea.

I do have a few pieces of advice about taste, however:

• Be selective about who you buy from.  The companies that do best at sourcing and selecting black teas are often not the best companies from which to buy green tea.  In particular, because black teas are a mainstay of British tea culture, and green teas are not, I recommend avoiding buying green teas from companies focusing on British traditions, and instead seeking out companies oriented towards Chinese and Japanese tea culture.
• Green tea and black tea are best brewed in different ways.  A quick recommendation is to use boiling water for black teas, and water well below boiling (about 180F/82C, about when small bubbles start to form in a heated pot) for green tea.
• Try different teas and form your own opinions.  No one can tell you what you like--only you can figure this out for yourself.  You may not wish to follow my (or anyone else's) recommendations of which teas to buy, or how to brew them.

It is very common for people in the U.S. to think green tea tastes bad because they either have only tried low-quality tea, or they have only tasted green teas prepared with boiling water, when they are types of tea that would taste much better if brewed with slightly cooler water.  Try giving green tea a bit more of a chance.  Buy from a retailer specializing in high-quality loose-leaf green teas, Chinese or Japanese, and put some care into brewing, before concluding that you don't like green tea.

Black tea, on the other hand, is a little bit less picky.

Green tea has been heavily over-hyped.  Even mainstream tea companies, including Teavana, make a lot of unsubstantiated or exaggerated claims about the health benefits of their teas, especially green and white teas.

For accurate information about tea and health, I recommend reading the page on tea on the micronutrient information center of the Linus Pauling Institute.  I trust this source, an impartial resource institute, much more than companies which have an interest in promoting tea.

The strongest evidence supports that consuming at least three cups of tea daily may modestly lower your heart disease risk.  Although there is a lot of hype about tea preventing cancer, there's not enough evidence to conclude that it actually prevents cancer or lowers cancer risk.  The same is true of weight loss.

Health risks or drawbacks:

Both green and black tea contain caffeine.  Although the amount is quite low, much lower than in coffee, the amount of caffeine in tea can still be enough that it can cause problems for caffeine-sensitive individuals, and for some people, it can contribute to insomnia if you drink tea too close to bedtime.

Both types of tea can be high in fluoride among natural food sources.  Andrew Weil took a stance on this issue, explaining that, while green tea does have about twice as much fluoride as black, he thinks concerns about fluoride in tea are overblown.  The fluoride may contribute to positive dental health, however!

There is also a little concern that tea may inhibit iron absorption, due to the tannins or other antioxidants binding to iron.  There's not much evidence that this actually causes a problem in normal, healthy individuals.  I researched this some time back and summarized my work on RateTea's page on tea and iron absorption.  If you are really worried about this but want to drink tea, you can take measures like drinking tea between meals, and making sure your iron-rich meals also contain natural sources of Vitamin C.