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Caffeine in tea: 40-50mg per cup of black tea, 25-40mg green tea, 15-25mg white tea, 30-50mg oolong, 50-70mg matcha, 2-5mg decaf, 0mg herbal infusions. Tea provides smoother caffeine response than coffee due to L theanine. NHS recommends maximum 400mg daily for adults; 200mg for pregnant women.
Caffeine by tea type
| Tea | Caffeine per 200ml cup |
|---|---|
| Black tea (Yorkshire, English Breakfast) | 40-50mg |
| Strong black tea (long brew) | 50-65mg |
| Earl Grey | 40-45mg |
| Green tea (mainstream) | 25-40mg |
| Sencha (Japanese) | 30-50mg |
| Matcha | 50-70mg |
| White tea (Bai Mu Dan) | 15-25mg |
| Oolong tea | 30-50mg |
| Pu erh | 30-45mg |
| Yerba mate | 30-45mg |
| Decaf tea | 2-5mg |
| Herbal infusions | 0mg |
Compared to coffee
- Drip coffee (200ml): 80-130mg.
- Espresso (30ml): 60-80mg.
- Strong black tea: 40-50mg.
Coffee has roughly 2-3x more caffeine per cup than tea.
L theanine modulation
L theanine in tea (10-30mg per cup) modulates caffeine response:
- Smoother peak.
- Reduced jitter.
- Calm alert focus.
Tea drinkers report different subjective experience to coffee at equivalent caffeine doses. Real mechanism.
NHS caffeine guidelines
- Adults: max 400mg daily.
- Pregnant women: max 200mg daily.
- Children: avoid caffeinated drinks generally.
- Adolescents: moderate consumption acceptable.
Caffeine half life
5-6 hours typically. Cut caffeine 6-8 hours before bed if sleep sensitive.
Factors affecting caffeine in tea
- Tea type (varies as above).
- Brew time (longer = more caffeine).
- Water temperature (hotter = more extraction).
- Leaf grade (smaller particles extract faster).
- Number of bags / amount of leaf.
- Water volume (smaller cup = more concentrated).
Decaf process
Modern decaf uses CO2 process, preserves polyphenols better than older methods. Residual caffeine 2-5mg per cup.
Caffeine sensitivity
Genetic factors mean some people metabolise caffeine fast (no sleep impact); some slow (small amount affects sleep). Know your sensitivity.
The number is a range you set
The printed figure assumes one set of conditions, and almost nobody brews exactly that. Most of the caffeine extracts in the first thirty seconds and around 95% by four minutes, so beyond that extra time adds tannin more than caffeine. The biggest swing is cup size: doubling a 150ml teacup to a 300ml mug roughly doubles the dose for the same bag, before any change in leaf, water temperature or steep. Origin shifts the baseline too, an Assam leaf carrying more than a Chinese one, which is why a strong tasting cup is not reliably high nor a delicate one reliably low. The deep treatment is the ultimate caffeine guide; for a base to match, a strong everyday black from Yorkshire Tea, single origin from Hyson, or the full tea shop.
FAQ
Tea caffeine? 40-50mg black; 25-40mg green; 15-25mg white.
Compared to coffee? Tea has roughly half.
L theanine? Smooths caffeine response.
NHS limit? 400mg daily adults; 200mg pregnancy.
Decaf? 2-5mg residual.
Curator's note: caffeine in tea is well defined and modulated by L theanine. The British 4-cup daily routine is well within NHS guidelines and provides sustained focus. Lee, Teas.co.uk, Tunbridge Wells.
Related on the wiki: Is tea addictive?
A natural follow-on: the English tea range and loose leaf range.
References cited
Caffeine-side companion reading
More from the tea wiki
- Green tea
- Black tea
- Oolong tea
- White tea
- Herbal tea
- Caffeine in tea
- How to make tea properly
- Loose leaf vs teabag
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