Water temperature for tea is about 80°C for green tea, about 90°C for oolong, and about 95°C for black tea. The kettle clicks off at 100°C; three cups wait on the counter. With a kettle that only boils, pour some cool water onto the leaves first and then the boiling water, or let the boiled water rest before you pour.
其沸，如魚目，微有聲，為一沸；緣邊如湧泉連珠，為二沸；騰波鼓浪，為三沸。已上水老，不可食也。
Qí fèi, rú yú mù, wēi yǒu shēng, wéi yī fèi; yuán biān rú yǒng quán lián zhū, wéi èr fèi; téng bō gǔ làng, wéi sān fèi. Yǐ shàng shuǐ lǎo, bù kě shí yě.
Meaning: “When it boils with bubbles like fish eyes and a faint sound, that is the first boil; when the edge bubbles like a spring of strung pearls, the second; when it surges like waves, the third. Beyond that the water is old and should not be used.” Lu Yu, The Classic of Tea (茶經), chapter 5.
Twelve centuries ago, tea makers judged water by eye and ear: steam, faint sound, edge bubbles, full boil. They had a pot of water and their own senses, and nothing else.
Why a few degrees change the cup
A tea temperature chart gives the target, but the cup explains why the target matters. Green tea at 80°C can taste grassy and clean. Push that same leaf with 100°C water and the finish can turn dry fast. Oolong at about 90°C has more room, buttery in one leaf and brisk in another. Black tea at about 95°C wants heat so the cup tastes full rather than thin.
In one 2023 lab extraction, Cheng, Xue and Yang steeped 7 teas, including green, oolong, black and jasmine, for 20 minutes at 25, 50, 70, 80, 90 and 100°C; measured extraction rose 3 to 10 times from 25 to 100°C. That is a lab steep, not drinking practice, but it shows the plain point: hotter water pulls out more from the leaf. Source
For green tea water temperature in daily brewing, our beginner guide gives the simple 80°C, 2–3 minute starting point, and Deng et al. found green tea brewed at 70–80°C tasted sweeter and less bitter and astringent than at 100°C. Source
Three ways to cool boiling water for tea
These methods are estimates. They are good enough for a morning mug, or a gaiwan on a desk, but they will not behave like a lab thermometer. Use them to get close, then adjust for taste: too bitter means cooler or shorter; too thin means hotter or longer.
| Method | Roughly what you get | Suits which tea |
|---|---|---|
| Add cool water first, then boiling water | About 20% cool water gives roughly 80°C; about 10% cool water gives roughly 90°C, using JING Tea’s estimate that each 10% cool water lowers the temperature by about 10°C. Source | Green tea at 80°C; oolong tea temperature near 90°C. |
| Let boiled water rest | About 30 seconds gives roughly 90–95°C; about 60 seconds gives roughly 80°C. Source | Oolong after a short wait; green tea after a longer wait. |
| Pour through a cool cup or jug once | No fixed number. A cool cup steals heat fast, so treat this as a rough drop rather than a measured method. | Useful when your kettle without temperature control has just boiled and you need a quick correction. |
The most repeatable home method is to add cold water to tea first, before the boiling water touches the leaves. For green tea, that means starting with about 20% cool water in the cup or pot, then adding the boiled water. The leaves meet water closer to 80°C, so the first contact is gentler.
What quietly steals heat: a cold pot and a high kitchen
A cold teapot can cool boiling water by about 10°C, according to JING Tea’s estimate. That helps green tea by accident, but it can weaken black tea. If you want 95°C for black tea, warm the pot first with hot water, empty it, then brew. Source
Altitude changes the top temperature before you even touch a cup. Engineering Toolbox gives these boiling points for water by altitude. A full boil in a high kitchen sits below the sea-level number. Source
| Altitude | Boiling point |
|---|---|
| 0 m | 100.0°C |
| 1,219 m | 95.7°C |
| 1,524 m | 94.7°C |
| About 1,981 m | 93.1°C |
The 1,200–1,500 m band is where Blossom Ritual’s family estates sit, so water there boils at roughly 95–96°C rather than 100°C. Before temperature-control kettles, people watched stages of water such as steam, stronger steam and full boil, and at altitude water may never reach 212°F even at a full boil. Source
When boiling water is the right call
For whole leaf black tea, use 95°C water or water just off the boil. Warm the pot first, especially if the pot is thick ceramic or has been sitting in a cool kitchen. This keeps the cup malty and brisk instead of flat.
For black tea, “boiling water” should mean close to 95°C when it reaches the leaves. Water at 100°C that hits a cold pot drops before the leaves open. If your kitchen is at 1,200 m, the kettle may already be boiling near the right range.
A cup from 1,200–1,500 m
Blossom Ritual is a Vietnamese specialty tea brand founded in Hanoi in December 2025, sourcing from its family's tea estates in Moc Chau (Son La) and Tam Duong (Lai Chau) — a 600-hectare estate at 1,200–1,500 m altitude.
Jasmine Bloom Green Tea is a Shan Tuyet green tea scented with jasmine, and it is the most sensitive of our teas to water that is too hot; we brew it at 80°C.
Frequently asked questions
Can you use boiling water for green tea?
For green tea, use about 80°C. Boiling water at 100°C can make green tea taste more bitter and astringent; Deng et al. found 70–80°C sweeter and less bitter than 100°C. That is why water temperature for tea matters most with green tea. If your kettle only boils, add about 20% cool water to the leaves first, then boiling water.
How do I get 80°C water without a thermometer?
Put cool water into the cup or pot first, then add boiling water. About 20% cool water gives roughly 80°C, using JING Tea’s estimate that each 10% cool water lowers the temperature by about 10°C. A 60-second rest after boiling is another rough route.
Does a cold teapot cool the water?
Yes. Boiling water poured into a cold pot can lose about 10°C, so a black tea meant for 95°C may start closer to 90°C. Warm the pot first when you want to keep heat.
Does water boil at a lower temperature at altitude?
Yes. At 1,219 m, water boils at 95.7°C; at 1,524 m, it boils at 94.7°C. At a high kitchen, a full rolling boil can still be below sea-level boiling water.
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