Last Updated on 11/22/2020 by Desmond
How much caffeine in tea? That’s a question troubling to many people. Researchers used to study different types of tea on the market, hope to found out the answer.
But the exact answer has not come so far.
The reason is very simple. There are too many factors that influence the caffeine amount in tea. That’s why most tea brands do not label the exact content of caffeine amounts on the package.
P.S. This post will not give an exact number of the caffeine content of different types of tea.
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Why We Care About The Caffeine Intake
Most people very careful about the caffeine content in tea. They just want to avoid the side effects of too much caffeine on their bodies.
Because of its stimulating effect, scientists believe that caffeine has many health benefits, such as increased watchfulness and attention, improved athletic performance, and a boost to the metabolism.
USDA and the EFSA both define safe caffeine consumption as less than 400 milligrams per day, less than 200 milligrams per intaking, or less than 3 milligrams per kilogram of body weight.
However, intaking caffeine that closes to the suggested amount one time will cause some problems. Such as anxiety, restlessness, and insomnia. Some people who are sensitive to caffeine may also cause symptoms such as headaches.
Besides, caffeine is considered mildly addictive, and some people may be more prone to experience dependency symptoms.
Such being this, how can we avoid intaking too much caffeine when having tea? What factors influence the content of caffeine in tea?
The Caffeine Content In Natural Raw Tea Leaves
All the true teas are made from the tea plant’s leaves (Camellia Sinensis), which contains caffeine naturally. (Herbal Tea do not belong to true tea, so most of them do not contain caffeine)
Before processing, the caffeine content of tea leaves depended on the part it picks from the plant.
We know that the young leaves contain more nutrition facts such as tea polyphenol, which will be more than the old leaves. Similarly, caffeine also higher.
Only talk about the raw tea leaves, that white tea may contain the most caffeine because white tea is made from the most tender tea buds and leaves. Some green tea is made without the tender buds but leaves, so it is in second.
Most of the dark tea is also made from the old tea leaves, even the tea stem. The natural caffeine contains lower.
Does that mean white tea and green tea have more caffeine than other types of tea?
The answer is No!
When we have tea, we drink the tea leaves’ extract rather than take the tea leaves directly. Our bodies will absorb only the part of caffeine dissolved in the water.
And the processing method influences the caffeine extraction in tea a lot.
How The Processing Method Influences The Caffeine In Tea
Fermentation
Tea is classified according to its processing methods.
We can see, most of the types of tea have been fermentation during processing.
The research found that during the fermentation process, microorganisms’ growth and reproduction would influence tea’s nutritional facts. The amount of caffeine also increases with fermentation time.
Notably, the complete-fermented black tea, partially-fermented oolong tea, and post-fermented dark tea have a higher coffee content than non-fermented tea such as green tea.
That’s why most of the studies suggested that black tea contains more caffeine than other types of tea.
Drying
For better storage and sales, tea masters will dry the tea leaves. Different types of tea have different drying way.
Black tea will dry by high-temperature baking, while white tea prefers to dry in a low-temperature environment, like outdoor under the sun.
The nutrition facts, including caffeine, will be translate or volatilization during drying. So the drying temperature and time will influence the caffeine amount in tea.
Cutting
What I thought, the cutting(shaping) may be the most significant factor that influences the extraction of caffeine in tea.
It is not difficult to understand that the larger the tea’s surface area, the wider its contact area with the hot water.
Take black tea and green tea as an example. The nutrition facts extraction efficiency of Matcha green tea(steaming green tea powder) and CTC black tea(broken black tea) are more than the whole-leaf ones.
So when we are brewing tea, we usually feel that the tea bag made of broken leaves will bring a more robust flavor faster than the whole-leaf.
Especially the Hong Kong-style milk tea can be said to extract the caffeine in black tea fully. A drink will make you keep activating all afternoon.
Besides, matcha can be said a most caffeine-intake tea drink. Green tea, which has a high caffeine content of its own, is ground into matcha powder. And when we have matcha, we consume all the tea leaves(powder).
That means we will intake all the caffeine contained in leaves! A cup of matcha can even stimulate the nerve as much as a cup of coffee.
Water Temperature Influence The Caffeine Extraction
As we just mentioned, high-temperatures can influence the extraction efficiency of caffeine in tea. Therefore, the temperature of brewing water is also an important factor.
Let’s see the recommended steeping temperature of each type of tea:
- Green Tea：80℃ – 90 ℃;
- Black Tea：95℃;
- Oolong Tea： 100℃;
- Yellow Tea： 80℃ – 90℃;
- White Tea： 70℃ – 80 ℃;
- Dark Tea： 100℃;
Besides, matcha powder’s recommended water temperature is about 60℃, and the cold brew tea is about 30℃.
The researchers suggested that the extraction efficiency of caffeine will be the most achieving at about 90℃. In the 60℃ case, the amount it extracted is only a half.
It is essential to control the water temperature when brewing. If you want a lower caffeine intake, consider brewing your tea at a lower temperature. But this will lose parts of the flavor of the tea and make other nutrition facts also hard to be extracted.
Steeping Time
The steeping time also greatly affects the extraction of caffeine.
Studies were used to test with various 20 brands of tea on the market. Took 6 oz of each tea (3 types of them take 8 oz), steeping in the water at 90-95 ℃ for 1,3 and 5 minutes.
The results showed that the caffeine extraction efficiency of 17 tea among are all increased over the steeping time and peaked at the fifth minute, except for three teas (two were herbal teas with no caffeine, and one was decaffeinated flavored tea with low caffeine content.)
Easy to see, as the steeping time increases, more of the tea’s nutrients (including caffeine) dissolve in the water.
In the cold brew tea case, even the water is cold, and it still extracts a certain amount of caffeine due to a long-time steeped.
Worth to know the Teh Tarik and the Hong Kong-style milk tea. They both have a long steeping time and making with CTC black tea. That why many people got insomnia after having them.
Other Factors
Besides the above 4, some other factors also influence the caffeine content in tea, also worth pay attention to:
- Tea origin region;
- Tea plant variety;
- Picking season;
- Further processing of tea leaves by the tea brand merchants (e.g., decaffeination);
- How much leaves you gonna take for brewing;
- Rounds that tea been brewed;
How To Control The Content Of Caffeine In Tea
After all these, we can see, so many factors influence the caffeine in tea we drunk. It’s hard to control the content of caffeine intake precisely.
So how can we do something to avoid to intake much caffeine when having tea? Here are 4 tips for you:
- Brewing the whole-leaf tea instead of the tea bag or broken tea;
- Avoid leafing the tea leaves or tea bag steep in the water for a long time;
- Choose the tea contains low caffeine, such as the decaffeinated tea;
- Avoid having too much tea one time;
Sometimes, we may want to take more caffeine from tea to get a refresh, and we could choose to brew a cup of CTC black tea. And matcha green tea also is an excellent choice.
Remember to pay attention to the amount; intake of too much caffeine may cause nervous tension and insomnia.
Also, everyone has a different sensitivity to caffeine. Best to choose the most suitable tea types and brewing method according to the individual’s feelings after drinking tea.
Reference
Caffeine Content of Brewed Teas
Effect of Microbial Fermentation on Caffeine Content of Tea Leaves
Thank you as always for the valuable information. I love tea but too much caffeine leaves me dehydrated and edgy. Washing the tea leaves and bags with hot water, brewing tea cold, and taking only a pinch of matcha powder per 8 oz. cup really helps me enjoy tea and get its stimulation without the negative effects of caffeine.