Q. What’s the difference between green and black tea? What about caffeine?

Written by Catherine Saxelby on Tuesday, 16 April 2013.
Tagged: caffeine, coffee, fluids, hydration, water

Q. What’s the difference between green and black tea? What about caffeine?
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Q. What's the difference between green tea and black tea? And can I drink green tea at night when I don't want caffeine?

A. Both green and black tea come from the leaves of the Camellia sinensis tea bush. Whether these tea leaves end up green or black depends on how they are processed or in other wors how they are 'finished' after being picked. 


Green tea is made from tea leaves that are simply steamed and dried soon after harvest.

Black tea is dried and crushed which allows the action of enzymes (which occur naturally in the tea leaves) to convert some of the simple catechins of green tea to more complex forms known as theaflavins and thearubigens. These compounds are responsible for the distinctive flavour and darker colour of black tea. They are also the well-known 'antioxidants' in tea responsible for much of its benefits.

Many people drink green tea in the belief it is caffeine free

Because it looks and tastes more like a light herbal tisane such as peppermint or chamomile, many people wrongly believe green tea to be caffeine-free. It's not.  Because it's derived from the SAME plant as black tea, green tea contains similar levels of caffeine (range 10 to 50 mg caffeine per cup).

So green tea is NOT the thing to drink before bed if caffeine disturbs your sleep. However, on a positive note, the caffeine content of all teas is only around one-third to one-half of that found in coffee so you don't get such a ‘jolt' of adrenalin when you drink it.

 Tea type

Caffeine in mg     

 Regular black tea, 1 cup 10-50mg
Green/Jasmine tea, 1 cup 30-50mg
Peppermint, 1 cup 0mg
Chamomile, 1 cup 0mg
Floral herbal, 1 cup 0mg
Rooibos redbush, 1 cup 0mg

Average caffeine values only as the final caffeine content depends on the type of tea leaves (or tea bag) and how long it was brewed. The longer the brew time, the higher the caffeine level in the final cup.

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