True teas, oxidation, and infusion basics

All true teas — white, green, oolong, black, and pu-erh — come from the same plant, Camellia sinensis; the differences between them come almost entirely from how the leaf is processed after picking, especially how much it's oxidized (exposed to oxygen, which darkens the leaf and deepens flavor). Water temperature that doesn't match the leaf's oxidation level is the single most common cause of a disappointing cup. Black tea is fully oxidized and tolerates near-boiling water (95–100°C), typically steeped 3–5 minutes — beyond that, excess tannins bring on bitterness.

Green tea is unoxidized or barely oxidized and far more delicate: near-boiling water scorches the leaf into a grassy, bitter cup, so it wants cooler water (roughly 70–85°C) and a shorter steep (2–3 minutes). White tea, the least processed of all, is even more delicate still and is typically steeped similarly cool to green tea. Oolong sits between green and black, partially oxidized, and is typically steeped around 85–95°C for a short time — many oolongs are also designed to be re-steeped several times, with each infusion revealing a different side of the leaf.

Pu-erh is fermented and aged rather than simply oxidized, giving it an earthy, deep character, and is typically brewed with a quick rinse-and-discard first pour to "wake up" the compressed leaf before steeping properly. Matcha is a distinct case: it's stone-ground green tea leaf whisked directly into water rather than steeped and removed, so the whole leaf is consumed — it's traditionally prepared with water well below boiling (around 70–80°C) whisked briskly in a zigzag motion with a bamboo whisk (chasen) until a light foam forms, since near-boiling water makes matcha taste bitter and grassy just as it does with green tea. Herbal infusions (mint, chamomile, hibiscus, and similar) aren't tea at all — no true tea leaf is involved — so there's no tannin-bitterness risk, and they're generally steeped near-boiling for longer, often 5 minutes or more, to fully draw out flavor.