People often inquire about the amount of Tea Caffeine. To understand the levels of tea caffeine, it would be helpful to understand the basics of how teas are made.
All teas (green, white, oolong, black) are made from the plant Camellia sinensis, which, like most plants in nature, contains caffeine to ward off predators.
Herbal teas like chamomile, hibiscus, ginger, and mint are made from their respective herbs and flowers which don't contain caffeine.
Here is an example of what caffeine looks like, as it can be seen when teas are being processed.
Which tea is highest in caffeine?
Unlike popular belief, the caffeine levels in tea do not correspond to whether if it's a green tea, oolong or black tea. Like anything else in nature, it's much more complicated.
The amount of caffeine in your cup of tea depends on a few main factors: brewing methods, processing styles, terroir, age of tea leaves and finally the cultivars of the tea plant.
- The higher the brewing temperature, the more caffeine gets extracted. (Brewing 5 grams of tea leaves in 100ml of water at 20 degrees Celsius yields 2.2 mg of caffeine, same tea and water ratio brewed at 100 degrees Celsius yields 67 mg of caffeine.)
- The length of brewing time changes the amounts of caffeine. Longer the brewing time will extract more caffeine.
- Roasting teas, like roasting coffee beans, is a finishing step. After the teas are made, they are roasted in either an electric oven or a bamboo roaster powered by charcoal. You can roast all types of tea (green, white, oolong, black). Exposure to heat encourages the solvency of caffeine molecules, which evaporates with water during the roasting process. The darker the teas are roasted, the less caffeine it contains.
- Broken tea leaves vs. whole tea leaves. Tea leaves used in most teabags are crushed into small pieces during production. Brewing broken pieces of tea leaves increase the surface area of caffeine extraction vs. brewing whole leave teas.
- Aging tea tend to lower the caffeine as molecules break down during the aging process. Older the tea, the less caffeine it has and the less stimulating.
- Warmer climates will induce higher caffeine content in the tea plant. Higher elevation typically has lower average temperature, and therefore produces teas with slightly less caffeine.
- Generally, Summer and Fall harvests have higher tea caffeine levels than cooler temperature harvests during Spring and Winter.
Age of Tea leaves
- Baby buds and younger tea leaves contain more caffeine than their mature counterpart.
- Different styles of tea production may require different types of harvested leaves. For example, Sencha (Japanese Green tea) makers tend to harvest younger leaves as younger leaves contain the vibrancy and sweetness that’s emblematic of a good quality green tea. Darjeeling 1st flush (Indian black tea) or Oriental Beauty (Taiwanese oolong tea) stylistically call for very young tea leaves as well (often baby buds) as part of their unique aroma profiles. These three styles of tea all have higher than average levels of caffeine in tea. Note, they are all processed differently and sit across various oxidation levels (green/oolong/black).
- Camellia sinensis plant contains an average of 2~5% of caffeine.
- There are thousands of cultivars within Camellia sinensis family (What are cultivars? Think Fuji and Honeycrisp apples are both cultivars of the apple family) and each tea cultivar will have slight variations on their natural caffeine content.
So, is it true that green tea has more caffeine...
It is likely that green tea has relatively higher amounts of caffeine, though it would be inaccurate to state the same in absolute terms. Good quality green tea tends to harvest younger leaves, therefore more caffeine.
Though based on the multi-layered caffeine influencing factors described above, it is possible to have a cup of Oriental Beauty oolong tea containing more caffeine than a cup of Hoijicha (roasted) green tea.
Does oolong tea have caffeine?
Yes. Oolong tea is made from the tea plant, which contains caffeine. Please refer to the above information to fully understand how caffeine in tea works.
How much caffeine is in a cup of tea vs coffee vs energy drink?
The below figures are generic reference points to provide a high level of approximation. They don't articulate the various factors that influence caffeine content in both coffee and tea. It is important to note from the chart that caffeine content for drip coffee and tea has a large range. It would be difficult to make an absolute comparison between these beverages.
Drip coffee (8oz): 131mg ~ 200mg
Espresso (1.5-2 oz): 100mg
Tea (8oz): 29mg – 99mg
Red bull (8oz): 75mg
Coffee caffeine vs. Tea caffeine
Tea Caffeine affects the human body differently because it forms different bonds with other substances when it’s digested. Tea derived caffeine binds with tannins (a polyphenol) which attenuate and stabilize the effect of caffeine. Tannins prevent caffeine from being released rapidly, therefore absorbed over a longer period.
Tea caffeine stimulates the central nervous system and the cardiovascular system by enlarging the diameter of the vessels in the cerebral cortex.
Coffee caffeine on the other hand has a direct effect on blood circulation through the coronary system, accelerating the heart rate.
What are the benefits of Tea caffeine?
Because tea caffeine takes longer to digest and its effects mainly influence the central nervous system, tea is more of an enduring stimulant rather than an excitant like coffee.
Instead of a coffee-derived caffeine high within minutes of consumption then follows by a deep energy drop, the effect of tea-derived caffeine sharpens the mind and increases concentration over time. It works to eliminates fatigue and enhances intellectual acuity.
source: Gascoyne, K., Américi, H., Desharnais, J., Marchand, F., Bourlier, K., Gascoyne, K., & Maison de thé Camellia Sinensis. (2018). Tea: History, Terroirs, varieties
Taiwanese teas caffeine content
Different styles of teas have a wide range of caffeine output. To make it easier for you to browse our selection of teas through a lens of caffeine, here is a study of Taiwanese tea caffeine output by style with three different brewing temperatures (80, 90, and 100 degrees Celsius).
This is a study done by the TRES, Tea Research Extension Station, a government agency that conducts R&D for tea in Taiwan.
To standardize the brewing ratio, the data is based on brewing 3 grams of tea with 150ml of water at 3 different temperatures.
Brewing times are slightly different based on how the teas are rolled.
Twisted types (Green, Baozhong, and Black): 5 min.
Half ball-shaped (Oriental Beauty): 5.5 min.
Full ball shape (High Mountain, Frozen Summit): 6 min.
Here is a key to our assortment:
Green: Green Sanctuary Vert
Baozhong: Baozhong Expert Pick
How much is too much caffeine?
The FDA and Mayo clinic recommends up to 400 mg of caffeine per day for healthy adults as an amount not generally associated with dangerous, negative effects.