Most people treat the caffeine in tea as a fixed number, the way it’s printed on a can of soda. It isn’t. Two cups from the same tin can differ by a factor of two or more, and almost all of that difference comes down to how you brew. Learning the few things that actually matter gives you something better than a figure on a label. It gives you control.
It Starts in the Leaf
Before water touches anything, the caffeine is already there. Dry tea leaf holds somewhere between 20 and 45 milligrams of caffeine per gram, and where a given tea lands in that range is decided by the plant long before it reaches your cup. (Ashihara, Sano & Crozier, 2008) Caffeine is a defense. The plant concentrates it in the youngest, most vulnerable growth as a natural insecticide, which is why buds and first leaves carry the most while older leaves down the stem carry less. A tea graded for tender buds, like a tippy Dian Hong or gong ting pu-erh, starts with more caffeine than one made from mature leaf. Season plays a part too, and spring-harvested leaf generally runs higher than autumn. (Bhuyan et al., 2021)
What Actually Controls Your Cup
Four things decide how much of that caffeine ends up in your cup, and not one of them is the color of the tea. Temperature sets the pace. Hotter water pulls caffeine faster, so near boiling the extraction is quick from the first seconds, while lower temperatures slow it without ever stopping it. This is the part most people get backwards. Brewing cooler does not make tea caffeine-free, it just stretches the same extraction over more time.
Time is the one people underestimate most. Caffeine is highly water-soluble and comes out fast and early, the curve steep at the start and flattening as the leaf gives up what it holds, so a brief steep releases a fraction and a long one approaches the full load. Dose is the simplest, since more leaf means more caffeine in play, and a gongfu setup with 5 to 8 grams in a small vessel starts with far more total caffeine than a Western cup using 2 to 3 grams. Leaf form is the quiet one, and it matters more than people expect. Broken leaf and the dust inside most teabags expose far more surface to the water, so they give up caffeine faster and in greater quantity than whole leaf. A 2025 study in Foods measured it directly, with the same black tea giving up around 39 milligrams per 200ml as a teabag against around 24 milligrams as loose leaf, brewed the same way. (Ayakdaş & Ağagündüz, 2025)
How Caffeine Moves Across Steeps
This is where it gets useful, especially for anyone drinking tea later in the day. Because caffeine is front-loaded, the early steeps carry most of it and the later ones carry very little. The most-cited measurement comes from Hicks, Hsieh and Bell, who in 1996 brewed several tea types across sequential steeps and found the first three infusions released roughly 69, 23, and 8 percent of the total. By the fourth or fifth steep, what remains is marginal. (Hicks, Hsieh & Bell, 1996)
| Steep | Approximate share of total caffeine |
|---|---|
| First | ~69% |
| Second | ~23% |
| Third | ~8% |
| Fourth onward | Trace amounts |
Later research on specific teas tells the same story. A 2020 study of Dahongpao oolong in Scientific Reports brewed the same leaves fourteen times and found about 70 percent of the caffeine gone within the first three steeps. (Wang et al., 2020) A 2025 study of Bingdao ancient-tree pu-erh in Foods tracked the same front-loading across many brews. (Foods, 2025) The pattern holds across categories. The leaf gives up its caffeine early. In practice, a tea you have already brewed several times in the morning is genuinely low in caffeine by the evening, not because of any trick but because the leaf is mostly spent.
The Rinse Myth
Gongfu practice often includes a quick rinse of the leaves before the first real steep, and it is widely claimed this washes away much of the caffeine. It doesn’t. A rinse of a few seconds removes only a small fraction, well under ten percent, because caffeine needs time and contact to dissolve, and to strip most of it out you would have to steep continuously for many minutes, by which point you would have brewed the tea anyway. (Hicks, Hsieh & Bell, 1996) The rinse is still worth doing. It wakes compressed or tightly rolled leaf, rinses away dust, and primes the first steep. Just don’t mistake it for decaffeination.
Why Tea Caffeine Feels Different from Coffee
By the gram, dry tea leaf often holds more caffeine than coffee beans, but in the cup it usually delivers less, because you use far less leaf per serving and brew it more gently. The more interesting difference is L-theanine, an amino acid found almost only in tea, which softens the edges of caffeine’s effect. Studies of the two together show gains in calm, sustained attention beyond what either produces alone. (Haskell et al., 2008; Nobre, Rao & Owen, 2008) L-theanine also extracts a little more slowly than caffeine, so as a session goes on and the caffeine depletes the balance shifts toward theanine, which is part of why experienced drinkers describe later steeps as quieter and calmer. The chemistry matches the feeling.
Drinking Tea at Night Without Staying Awake
You can put all of this to use. Run a full session in the morning or early afternoon on a tea built for many steeps, a tightly rolled oolong or a compressed pu-erh, and by the time you finish you will have pulled out most of the caffeine. Drain the leaves well and refrigerate them rather than leaving them wet at room temperature. In the evening, brew the same leaves again with slightly hotter water and longer steeps, coaxing out what little is left. The cup will be softer and thinner, a quiet echo of the morning, but still recognizably that tea. This works because you have run the extraction curve close to its end during the day, not because of a rinse or a marketing claim. Delicate greens are poor candidates, since they exhaust quickly and can turn off-flavored when stored wet.
A Note on Numbers
You will find a lot of confident, milligram-precise caffeine figures online. Treat them with suspicion. Real measurements swing widely with cultivar, leaf grade, water temperature, particle size, and steep time, and any honest figure is a range rather than a point. The values here come from peer-reviewed work and are meant as direction, not gospel. The reliable knowledge was never a single number. It is knowing which levers move the caffeine, and in which direction.
Sources
Ashihara, H., Sano, H. & Crozier, A. (2008). Caffeine and related purine alkaloids: biosynthesis, catabolism, function and genetic engineering. Phytochemistry, 69(4), 841–856. doi:10.1016/j.phytochem.2007.10.029. leaf-position caffeine distribution and insect-deterrent function.
Bhuyan, L.P. et al. (2021). Catechin and caffeine content of tea (Camellia sinensis) leaf significantly differ with seasonal variation. Journal of Food Composition and Analysis. ScienceDirect. seasonal and cultivar variation in leaf caffeine.
Hicks, M.B., Hsieh, Y.-H.P. & Bell, L.N. (1996). Tea preparation and its influence on methylxanthine concentration. Food Research International, 29(3–4), 325–330. ScienceDirect. sequential-steep caffeine distribution (~69 / 23 / 8 percent); primary source for the rinse analysis.
Ayakdaş, G. & Ağagündüz, D. (2025). Determination of L-theanine and caffeine contents in tea infusions with different fermentation degrees and brewing conditions using the chromatographic method. Foods. PMC. teabag vs loose-leaf caffeine (39 vs 24 mg/200ml in black tea).
Wang, Z. et al. (2020). Prediction of suitable brewing cuppages of Dahongpao tea based on chemical composition, liquor colour and sensory quality in different brewing. Scientific Reports, 10, 622. Nature. ~70 percent of caffeine released in the first three of fourteen steeps.
Dynamic changes in sensory quality and chemical components of Bingdao ancient-tree tea during multiple brewing. (2025). Foods, 14(14), 2510. doi:10.3390/foods14142510. front-loaded caffeine across sequential infusions of raw pu-erh.
Haskell, C.F. et al. (2008). The effects of L-theanine, caffeine and their combination on cognition and mood. Biological Psychology, 77(2), 113–122. doi:10.1016/j.biopsycho.2007.09.008. caffeine plus L-theanine effects on attention and alertness.
Nobre, A.C., Rao, A. & Owen, G.N. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific Journal of Clinical Nutrition, 17(S1), 167–168. PubMed. L-theanine and alpha brain-wave activity.