First identified as "theine" in 1827, caffeine was discovered in tea before it was found that tea's "theine" was identical to coffee's caffeine. Although the caffeine in both beverages is the same, the experience varies due to three main factors:
- A lower caffeine content in tea, especially in green and white teas, due to shorter brewing times and lower temperatures.
- The presence of L-theanine, an amino acid exclusive to tea, which provides relaxation without affecting alertness.
- The high antioxidant levels in tea slow down caffeine absorption, leading to a more gradual increase in alertness without a crash.
Contrary to popular belief, tea does not contain more caffeine than coffee when brewed. A 2004 British study found that the average caffeine content in a cup of tea was 40mg, compared to 105mg in a cup of drip coffee.
Caffeine content in tea is affected by factors like brewing method, steeping duration, and the tea plant's leaf position. The youngest leaves at the top of the plant have higher caffeine and antioxidant concentrations. The most significant impact on caffeine content comes from water temperature and steeping time. Oxidation does not influence the amount of caffeine in tea, despite the popular myth.
It is difficult to make generalized statements about caffeine levels in different tea types, but certain varieties stand out in their respective categories:
Higher caffeine content:
- Silver Needle (White Tea)
- Matcha (Green Tea)
- Assam (Black Tea)
- Ceylon (Black Tea)
- Darjeeling (Black Tea)
Lower caffeine content:
Tea bags and finely ground loose tea yield higher caffeine infusions than regular loose tea. Comparatively, coffee and most sodas have at least twice the caffeine content versus a cup of tea.
Caffeine tolerance varies among individuals, and decaffeinated tea is not entirely caffeine-free, containing 5-10 mg per cup. The myth of creating decaf tea by briefly steeping and discarding the liquor is incorrect, as this method removes both caffeine and the beneficial antioxidants.
To completely avoid caffeine, switch to herbal teas, which are naturally caffeine-free, unlike the Camellia sinensis plant that produces all true tea varieties. Herbal infusions, such as Chamomile, Rooibos, and Tulsi, are made from plants unrelated to Camellia sinensis, offering caffeine-free alternatives.