Water, coffee, tea, infusions and other drinks: composition, preparation, storage and everyday consumption.
There is no universal cup. As a broad guide, the FDA lists brewed coffee at about 80–100 mg caffeine per 8 fl oz and green or black tea at 30–50 mg. Two grams of matcha could provide roughly 38–89 mg based on published dry-powder analyses; a yerba-mate review reports about 80 mg in a 150 ml cup, with repeated traditional pours potentially raising the session total much higher.
Decaf does not mean caffeine-free. The FDA says an 8 fl oz cup of decaf coffee typically contains about 2–15 mg caffeine, compared with roughly 80–100 mg in regular brewed coffee. The reduction is large, but the residual amount can still matter to someone who is very caffeine-sensitive.
Coffee aroma fades fastest with exposure to air, moisture, heat and light. The National Coffee Association recommends buying smaller amounts, storing coffee in an airtight opaque container in a cool dark place, and grinding whole beans only when needed. As a freshness guide after opening, it lists about 1–3 weeks for roasted beans at room temperature and 1–2 weeks for ground coffee when properly stored.
Whole-bean coffee usually holds aroma longer because most of the bean remains protected from air. Grinding dramatically increases surface area and speeds volatile loss, which is why the National Coffee Association recommends grinding only what you need immediately before brewing when practical. Pre-ground coffee wins on convenience, not on a different nutrition profile.
Matcha is a type of green tea, not a different plant. Its leaves are shade-grown before harvest, processed into tencha and finely milled, and the powder is consumed rather than discarded after steeping. Reviews report roughly 18.9–44.4 mg caffeine per gram of matcha, so the amount of powder used strongly affects the dose.
The FDA gives about 80–100 mg caffeine for an 8 fl oz cup of brewed coffee. Published matcha analyses range around 18.9–44.4 mg per gram, so a 2 g preparation could provide roughly 38–89 mg. The ranges can overlap: coffee is often the higher-caffeine serving, but a strong matcha can get close.
Green and black tea come from the same species, Camellia sinensis. Green-tea processing quickly limits enzymatic oxidation; black tea is deliberately oxidized much further, converting many catechins into theaflavins and thearubigins. Caffeine does not cleanly separate the two: the FDA gives about 30–50 mg per 8 fl oz as a broad reference for either green or black tea.