🍵 Tea: The World in a Cup

What you’ll learn

1. One Plant, Many TeasEstablish that all true tea comes from one plant, Camellia sinensis.Green, black, white, and oolong teas are all leaves of a single evergreen shrub, Camellia sinensis; their differences come from processing, not botany. Herbal 'teas' contain no Camellia sinensis and are properly infusions or tisanes.
2. Oxidation: The One VariableExplain oxidation as the single variable that defines the classic tea types.Oxidation — enzymatic browning like a cut apple — is controlled to make different teas. Green tea is heated to stop it immediately, white tea is barely processed, oolong is partially oxidized, and black tea is fully oxidized. One dial produces the whole spectrum.
3. From Leaf to CupTrace the leaf through processing and identify heat timing as the decisive step.Tea passes through plucking, withering, rolling, oxidizing, firing, and drying. The decisive moment is when heat is applied: early heat stops oxidation (green), delayed heat lets it run (black). The same leaf becomes different teas through timing alone.
4. The Classic Types, Side by SideCompare the classic types by oxidation level and introduce matcha, yellow, and dark teas.Green (minimal), white (very light), oolong (partial, 10–80%), and black (full) line up along the oxidation scale with characteristic flavors. Matcha is powdered green tea drunk whole; yellow tea is a mellowed green, and dark teas like pu-erh are microbially fermented — a separate process from oxidation.
5. Terroir: Why Where MattersIntroduce terroir and human choices as what distinguish teas of the same type.Beyond oxidation, a tea's character depends on terroir — altitude, climate, soil, and cultivar — plus human choices of plucking standard and season. High mountain gardens like Darjeeling concentrate flavor; genetics, terroir, and craft stack to make each tea unique.
6. The Caffeine TruthCorrect common caffeine myths and explain tea's calm energy.Caffeine comes from the plant and is stable through processing, so oxidation (tea type) barely affects it; variety, leaf age, and brewing matter more. Rough per-cup ranges (green ~20–45 mg, oolong ~30–50, black ~40–70) overlap and sit below coffee (~95 mg). Tea's L-theanine pairs with caffeine for a gentler, steadier alertness.
7. Brewing It RightGive practical, sourced guidance on water temperature and steep time by tea type.Delicate green and white teas need cooler water (about 160–185°F) or they scorch bitter; robust black tea wants near-boiling water (200–212°F). Over-steeping releases bitter tannins. Matching temperature and time to the tea completes the journey from leaf to cup.
8. Tea and EmpireSketch tea's history and its outsized role in trade and empire.Tea originated in China, spread to Japan (the tea ceremony) and by the 1600s to Europe, where British demand drove tea clippers, Indian plantations (Assam, Darjeeling), and the 1773 Boston Tea Party. Tea's role in the Opium Wars is covered in the companion China course; all of it traces back to one plant.

Questions this course answers

Grounded in trusted sources

• Harold McGee, 'On Food and Cooking' (Scribner, rev. 2004) — chapter on tea and oxidation
• Comparative analyses of Camellia sinensis processing — green (minimal oxidation), oolong (~10–80%), black (full); caffeine stable through processing (peer-reviewed and tea-industry sources consulted this session)
• Tea caffeine per cup (approx., tea-vendor and reference guides): green ~20–45 mg, oolong ~30–50 mg, black ~40–70 mg; coffee ~95 mg
• Steeping temperature/time guides — Harney & Sons and other tea-vendor brewing charts (green 160–185°F/1–3 min; white 175–185°F/3–5 min; oolong 180–205°F; black 200–212°F/3–5 min)
• Standard histories of tea (origin in China; spread to Japan and Europe; East India Company, Assam/Darjeeling plantations; 1773 Boston Tea Party)
• International Tea Committee / FAO — tea as the world's most-consumed beverage after water

Every Wunder lesson is built from real, reputable sources — never invented.

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