Both green and black tea naturally contain caffeine. Usually, black tea contains more caffeine than green tea.
In this article, I’ll compare green vs. black tea caffeine and explain why black tea almost always has more caffeine than green tea.
Green Tea vs. Black Tea Caffeine
Green tea contains less caffeine than black tea. The caffeine content in green tea is usually 30 mg per 8-oz cup, whereas black tea typically contains 47 mg of caffeine per 8-oz cup.
In both teas, the caffeine levels vary, and for green tea, they are usually in the range of 20 to 50 mg of caffeine per cup. For black tea, the caffeine levels are between 40 and 80 mg per cup.
As you can see, black tea practically always has more caffeine than green tea.
Additionally, high-quality Matcha green tea is also higher in caffeine compared to regular green tea.
The caffeine levels in matcha green tea powder are usually 64 mg per 8 fl oz cup, and they can be in the range of 38–88 mg of caffeine per cup.
I must mention here that the caffeine levels in tea, whether black or green, vary depending on the tea plant cultivar and how it’s grown.
Additionally, the brewing temperature and steeping time also have a significant impact on the caffeine levels in your cup of tea.
Now let’s see some details about the caffeine in black and green tea.
Caffeine in Green Tea
There are many factors that affect how much caffeine there will be in some green tea. Those factors are:
- Period of harvest – Earlier harvests contain higher caffeine levels.
- Broken vs. Whole Leaves – Broken leaves release caffeine faster in your cup than whole leaves.
- Temperature and Steep Time – Higher water temperature and longer steep time result in more caffeine extracted.
Additionally, different types of green tea contain different caffeine levels. For example, Japanese green teas are usually higher in caffeine compared to Chinese green teas.
Here are some examples of high, medium, and low-caffeine green teas:
- High Caffeine: Gyokuro and Matcha.
- Medium Caffeine: Sencha, Longjing.
- Medium-Low Caffeine: Hojicha
- Low Caffeine: Bancha, Genmaicha.
To learn more about the caffeine in green tea and how it compares to that in coffee, go here.
Caffeine in Black Tea
Different types of black tea contain different levels of caffeine. Much like in green tea, many factors affect the caffeine levels in certain black tea varieties.
Each type of black tea is unique to the place in which it is cultivated (India, China, Sri Lanka). Every type is distinctive in its own way, and they all contain different levels of caffeine.
Here are the caffeine levels of the most popular types of black tea:
- Assam: 60-112 mg/cup
- Darjeeling: 40-70 mg/cup
- Ceylon: 42-78 mg per/cup
- Yunnan: 30-60 mg per/cup
Also, there are some very popular black tea blends with these caffeine levels:
- Earl Grey Tea: 40-80 mg per cup
- English Breakfast Tea: 30-60 mg per cup
As you can see, the caffeine levels in black tea vary, but usually, no matter what type or blend of black tea you choose, it will always contain more caffeine than green tea.
More details on the caffeine content in black tea can be found here.
Why Does Black Tea Have More Caffeine Than Green Tea?
In most cases, black tea contains more caffeine than green tea, but due to the many factors affecting the caffeine content in tea (mentioned above), there are examples where you can get a very strong energy boost from green tea too.
For instance, a cup of late-harvested black tea might contain less caffeine than a cup of fresh Jasmine green tea or shaded Gyokuro green tea.
Additionally, mature leaves have less caffeine than buds, so green tea with more buds may be stronger than black tea with mature, unbroken leaves.
Longer steep times at higher water temperatures extract more caffeine from the tea leaves. Furthermore, compared to other types of tea, black tea’s oxidized leaf allows for greater extraction of caffeine.
Caffeine in Coffee Compared to Black and Green Tea
An average 8-oz cup of black-brewed coffee contains 95 mg of caffeine.
Like with green and black tea, the caffeine levels in coffee vary depending on the type of coffee.
- A single shot of espresso contains 63 mg of caffeine per 1 oz (29ml)
- Drip or Filtered Coffee contains between 115 and 175 mg of caffeine per 8 fl oz cup
- Decaf Coffee provides less than 3 mg of caffeine per 8 fl oz cup
When compared to black and green tea, a regular cup of black coffee usually contains more caffeine.
It is worth noting that tea leaves contain approximately 3.5% caffeine, whereas unbrewed coffee beans contain only 1.1-2.2% caffeine.
This means that although there is technically more caffeine per mg in tea than in coffee, the amount of caffeine changes after hot water is added and the coffee or tea leaves are brewed.
More caffeine is extracted from the beans during the coffee-brewing process because hotter water is used. Additionally, you use more coffee beans than tea leaves when making a cup of coffee.
So, this is the main reason why brewed coffee typically contains more caffeine per serving than green or black tea.
L-theanine in Green vs. Black Tea
L-theanine is an amino acid found in some fungal species and in the tea plant Camellia sinensis. All teas produced from the leaves of this plant (green, black, white, oolong) contain varying levels of L-theanine.
Why is L-theanine so important? The combination of L-theanine and caffeine in tea helps to improve focus, reduce stress, and boost energy that lasts longer than the energy boost from coffee’s caffeine.
Green tea contains approximately 6.56 mg of L-theanine per gram of tea leaves, while black tea contains around 5.13 mg of L-theanine per gram of tea leaves according to a 2016 study.
As you can see, both black and green tea contains L-theanine, making them excellent substitutes for coffee for people who want a mood boost without coffee’s recognizable restlessness.
Both green and black tea naturally contains caffeine. Green tea typically has less caffeine than black tea. This is not always the case.
For example, shade-grown gyokuro and matcha green tea may sometimes contain higher caffeine levels than black tea made from mature leaves (harvested later in the season).
Black tea will almost always be slightly stronger than green tea, and the best way to determine the amount of caffeine in your tea is to ask your tea supplier.
Finally, if you want a stronger tea with higher caffeine levels, opt for black tea. If you prefer lighter tea with lower caffeine levels, opt for green tea.
No matter which tea you choose, I’m sure you’ll enjoy it. Both teas are top-notch, so you should experiment with them to discover your favorite.