Tea & Coffee Deep-Dive
Caffeine, L-Theanine & Polyphenols

15 beverages compared — what's in each cup, why the brew matters, and how to pair them to the effect you want.

Caffeine per cup
L-Theanine content
Polyphenol classes
Brewing guide

Reading the Table

Values are per standard serving (coffee ≈ 240 mL drip / 30 mL espresso; tea ≈ 240 mL brewed 3–5 min). Polyphenol amounts vary by leaf, brew time and water temperature — these are typical-cup ranges. Daily caffeine ceiling: ≤ 400 mg for healthy adults, ≤ 200 mg in pregnancy.

Beverage Caffeine L-Theanine Key Polyphenols Best For
Espresso
30 mL shot
63 mg Chlorogenic acid (high) Quick alertness, post-meal
Drip Coffee
240 mL
95-200 mg Chlorogenic acid 70-200mg Sustained morning alertness
🧊
Cold Brew
240 mL
153-238 mg Chlorogenic acid (slightly less) Smoother, lower acidity
🥤
Instant Coffee
240 mL
60-80 mg Chlorogenic acid (reduced) Convenience
Decaf Coffee
240 mL
2-15 mg Chlorogenic acid intact Polyphenols without caffeine
🍂
Black Tea
Camellia sinensis fully oxidised
40-70 mg 5-15 mg Theaflavins · Thearubigins Cardiovascular · gentle alertness
🍵
Green Tea
Steamed / pan-fired
20-40 mg 15-30 mg EGCG 50-100mg · Catechins Calm focus · cancer cohort data
🍃
Matcha
Whole-leaf powder
60-80 mg 20-40 mg EGCG ≈ 134mg · Chlorophyll Highest catechin density
🤍
White Tea
Minimally processed buds
15-30 mg 15-25 mg Catechins (highest per gram) Gentle hydration with polyphenols
🍶
Oolong Tea
Partially oxidised
30-50 mg 10-20 mg Theasinensins · partial catechins Balanced caffeine + body
🟫
Pu-erh
Microbially fermented
30-70 mg 10-20 mg Statins (lovastatin trace), polysaccharides Lipid profile · digestion
🟥
Rooibos
Aspalathus linearis (S. Africa)
— (caffeine-free) Aspalathin · Nothofagin Evening / caffeine-sensitive
🧉
Yerba Mate
Ilex paraguariensis
30-50 mg Saponins · Chlorogenic acid Alertness without jitters
🌼
Chamomile
Matricaria recutita
Apigenin (mild sedative) Evening · sleep
🌿
Peppermint Tea
Mentha piperita
Menthol · Rosmarinic acid Digestion · IBS · headache

Compare

Brewing Quick-Guide

Get the polyphenols out without making it bitter.

Water Temperature Cheat Sheet

White / Green 70–80°C — hotter water makes catechins bitter
Oolong 85–90°C
Black / Pu-erh 95°C
Herbal (rooibos, chamomile, mint) 95–100°C, 5–7 min
Drip Coffee 90–96°C, 4–6 min total brew time
Espresso 90–96°C, 25–32s extraction at 9 bar

When to Drink What

Morning — coffee or black tea for fast alertness
Mid-morning focus — green tea or matcha (L-theanine smooths peaks)
Afternoon (≥ 6 h before bed) — last caffeinated cup; switch to white or oolong
Evening / wind-down — rooibos, chamomile, peppermint, decaf
Post-meal digestion — espresso (small), peppermint, oolong

Cautions

Total caffeine ≤ 400 mg/day (≤ 200 mg in pregnancy)
Tea / coffee within 1 h of iron-rich meals reduces non-heme iron absorption by 50–60%
Energy drinks combine caffeine + sugar + taurine + guarana — easy to exceed safe caffeine quickly
Caffeine half-life lengthens with some SSRIs and oral contraceptives — afternoon caffeine may disturb sleep more than expected
Unfiltered coffee (French press, Turkish, boiled) raises LDL — cardiac patients use a paper filter

The "Calm Focus" Stack

The most-studied flavour-led nootropic combo is naturally present in matcha and green tea: 60–100 mg caffeine + 30–50 mg L-theanine. L-theanine smooths the spike, sharpens attention without jitters. Easier than buying both as supplements.