Black Tea Caffeine: Debunking the Myths

Black tea is one of the most popular teas in the world, and for a good reason. It's rich in flavor and has many potential health benefits. However, there are many myths surrounding the caffeine content of black tea.

As a tea sommelier, I often get asked, “Does black tea have the most caffeine?” And my answer is “yes and no.”

So in this article, we'll explore the truth about black tea caffeine:

  • Myth or Reality: Black Tea is High in Caffeine
  • Factors that Influence the Caffeine Content of Black Tea
  • The Caffeine Content of Different Types of Black Tea
  • Reason Tea Companies List Black Tea as High in Caffeine
  • How to Control your Caffeine Intake from Black Tea

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Myth or Reality: Black Tea is High in Caffeine

One of the most common myths about black tea is that it is high in caffeine. This myth is perpetuated by the fact that black tea is often marketed as a "pick-me-up" and is often consumed in the morning to help wake up and start the day. However, the truth is that black tea is not necessarily high in caffeine compared to other teas.

Note that the color of the brewed tea and the oxidation of the tea leaves don't significantly affect the caffeine level. So what are the factors that impact the level of caffeine in black tea?

Factors that Influence the Caffeine Content of Black Tea

1. Maturity of Tea Leaves

The caffeine content of tea leaves can vary depending on the part of the tea plant used. Younger leaves and buds tend to contain more caffeine than older leaves. So, teas made with younger leaves, such as first flush Darjeeling or tips-only tea, may have higher caffeine content than teas made with older leaves.

2. Variety of Tea Plants

While Camellia sinensis var. sinensis is the most common variety of the tea plant, a wide range of varieties that are used to produce different types of tea.

For example, Assam tea is made from Camellia sinensis var. assamica, which is native to the Assam region in India. This variety is known for producing larger leaves that contain more caffeine than other tea varieties.

On the other hand, Darjeeling tea is made from a variety of Camellia sinensis called Camellia sinensis var. sinensis, which is native to China and is known for producing smaller leaves and generally lower caffeine content.

Some teas, like our Boseong Korean Black Tea, are made from a hybrid of Camellia sinensis var. sinensis and Camellia sinensis var. Assamica. Given its hybrid nature, the level of caffeine from such varieties sits in the mid-range between the two varietals.


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3. Soil and Climate Conditions

The soil and climate conditions in the regions where tea is grown can impact the caffeine content of the tea leaves.

Generally speaking, hot and humid regions with nitrogen-rich fertile soil contribute to the higher caffeine content in the leaves. The tea plant produces caffeine as a natural pesticide, which helps to protect the plant from insects and other pests that are more prevalent in the hot and humid conditions of the region. This natural defense mechanism can result in tea leaves with higher caffeine content.

Since Assam has a hot and humid climate, Assam teas tend to have higher caffeine content than Darjeeling teas grown in cooler weather.

Boseong of Korea has cooler temperatures than Darjeeling but is lower in altitude. So, in this case, it’s hard to compare the level of caffeine between Darjeeling and Boseong Korean Black Tea just based on the soil and climate conditions of the two regions.

4. Processing Method

The processing method used to make the tea can also affect the caffeine content.

Assam tea is typically processed using the CTC (crush, tear, curl) method, which involves crushing the leaves into small pieces. Its larger surface area causes more caffeine to be extracted during brewing.

Boseong Korean Black Tea, on the other hand, is hand-picked from Mr. Kim’s garden and processed using the orthodox method, which involves withering, rolling and drying the leaves. Large whole leaves have a smaller surface area, resulting in less caffeine extracted during brewing.


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5. Brewing Process

Recently, scientific testing has shown that variations in caffeine levels of different tea types have more to do with brewing than processing.

For example, using hotter water to brew tea will extract more caffeine than using cooler water. Black tea, which tends to use boiling water, will have more caffeine than other types of tea.

Steep time also influences the caffeine present in tea. The longer you infuse your tea leaves, the higher the caffeine level will be. Since black teas tend to be steeped for more extended periods, they tend to be higher in caffeine. Also, reusing tea leaves for multiple infusions can lead to a higher caffeine concentration in the later infusions.

Overall, the caffeine content of black tea can be influenced by several factors, including the maturity of tea leaves, the variety of tea plants, soil and climate conditions, and the brewing process. Understanding these factors can help you decide which teas to choose and how to brew them to control caffeine intake.

The Caffeine Content of Different Types of Black Tea

Now we understand different factors that influence the caffeine content of black tea, let’s compare the caffeine amount across different black tea types, from highest to lowest.

  • Assam tea or other crushed tea leaves from Assamica tea plants growing in a hot and humid climate: estimated 80mg of caffeine per 8 oz cup
  • Yunnan black tea or other black tea from Assamica tea plants growing in a high altitude, cooler climate: ~65mg of caffeine
  • Darjeeling tea or other black teas from younger leaves from Sinensis tea plants growing in a high altitude, cooler climate: ~50 mg of caffeine
  • Boseong Korean Black Tea or other Korean or Japanese black teas from younger leaves from a hybrid of Sinensis and Assamica varietals, growing in a lower altitude but cooler climate: ~40mg of caffeine
  • Keemun black tea or other Chinese black teas from younger leaves from the Sinensis varietal, growing in a high altitude with a temperate climate: ~30 mg of caffeine.

Note that this is an estimate as we don't know whether the variety of tea plants more significantly affects the caffeine content than the soil and climate conditions.


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Reason Tea Companies List Black Tea as High in Caffeine

So why do other tea companies say black teas are high in caffeine?

That is because big companies use their brewed tea to test the amount of caffeine. And their brewed cup usually consists of lower-quality crushed mature tea leaves brewed at high temperatures. Therefore, when they compare the caffeine content between black tea and other teas, like green tea, brewed at lower temperatures, it has lower caffeine content.

Smaller tea companies like us do not have the means to test each of our small-batch tea for its caffeine content. So how would you have more control over your caffeine intake?

How to Control your Caffeine Intake from Black Tea

The two factors you can control the most are brewing and consumption amount.

If you want to decrease your caffeine intake, experiment with shortening your brewing time or only drinking the earlier infusions of the leaves.

And as you consume your tea, look closely at how your body responds. L-theanine in tea regulates caffeine absorption, so the effects of caffeine from tea are different from those of coffee. So you likely will feel alert but without the spikiness of coffee caffeine.

The easiest way to experiment with the ideal tea consumption amount is to start with a cup in the morning and gradually increase the amount based on your body’s reaction.

Are you interested in learning more about caffeine and other tea types? Read more articles here or sign up for our weekly newsletter.

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