--- title: 'Heat sources for tea' url: 'https://howtotea.me/teaware/utensils/heat-sources' markdown: 'https://howtotea.me/teaware/utensils/heat-sources.md' lang: en date: '2026-10-25' description: 'What to heat tea water on: the Chaozhou charcoal brazier, alcohol burner, electric kettle, induction. Which charcoal to buy and why a closed room is risky.' --- # Heat sources for tea Editors · October 25, 2026 · 9 min read An electric kettle heats water faster and cheaper than charcoal, gas or alcohol: 80–90% efficiency against 30–60% for gas. People still burn charcoal for the ritual and the "lively fire", but then they need ventilation and a carbon monoxide alarm. ![A small clay stove with a water kettle and a cast-iron kettle on its trivet](https://howtotea.me/images/c/o/v/e/r/cover-c28da525.webp) Illustration Heat sources Electric kettle: 80–90% efficiency Induction: 79% in one home test; needs a flat magnetic base Gas: about 40%, range 30–60% Alcohol burner: 1 l of water boils in 15 minutes Chaozhou stove: 12–25 or 25–40 cm tall by the 2021 standard CO in a room: 700 ppm in 50 minutes from 10 pieces of charcoal Fire for tea comes down to two things: the fuel and what it burns in. Charcoal goes into a stove with a draft opening, alcohol into a burner with a wick, and electricity needs no flame at all. The choice affects speed, effort and safety. It affects the taste of the tea less than people tend to claim. The [water kettle](https://howtotea.me/teaware/utensils/kettles) and the [water itself](https://howtotea.me/brewing/basics/water) are separate topics; this is about what sits under the kettle. ## Charcoal and "lively fire" In the Classic of Tea (8th century) Lu Yu ranks charcoal first among fuels and "sturdy wood" second. He rules out charcoal that has soaked up grease, resinous wood such as cypress and juniper, and scraps of old objects: old wood, he writes, has a taste of its own. Li Yue, also of the Tang, wants water boiled on a "lively fire", meaning charcoal with flame: water should not boil chaotically, and only such a fire takes it through the three stages of boiling. Writing in the Ming, Xu Cixu adds that the charcoal should first be heated red-hot to drive out the smoke. In Chaozhou the practice lives on. A red clay stove burning olive-pit charcoal is one of the "four treasures" of [gongfu cha](https://howtotea.me/traditions/china/living-traditions/chaozhou-gongfu), and "light the stove" and "boil water on olive charcoal" are among the steps of the tradition added to China's national intangible heritage list in 2008. Several kinds of charcoal are used: - **Olive.** Pits of black olive with the pulp and kernel removed, fired in a kiln. The heat is even, the aroma light. Five jin of pits make about one jin of charcoal, which is why it costs so much. - **Jiaozhi.** Hardwood fired until the resins burn out. A good piece rings when struck and shines where it breaks. - **Longan and lychee.** Cheap, easy to light and hot, but they burn out fast. They go in as a base, with olive charcoal on top. - **White charcoal.** Japanese binchotan from ubame oak is fired for about 120 hours at 240 °C, then at about 1000 °C. It is slow to light and holds heat for a long time. The real thing rings like metal; a dull knock gives away ordinary charcoal. - **Black charcoal.** Nara or kunugi oak, 400–700 °C. Soft and quick to heat. [Chanoyu](https://howtotea.me/traditions/japan-and-korea/chanoyu) calls for young kunugi. - **Coconut-shell briquettes.** They burn evenly, with a less lively flame. Good for beginners. Avoid scented barbecue briquettes, wax fire starters (they smoke and melt), and pine or mixed charcoal. ## Stoves: Chaozhou, Japanese, open Under the 2021 group standard, a Chaozhou stove is made of red or white clay mixed with quartz or river sand and then fired. A low one stands 12–25 cm, a tall one 25–40 cm. The 2023 municipal regulation gives a diameter of 12–20 cm and adds a copper hammer, tongs and shovel, charcoal sticks and a goose-feather fan. Three lugs sit on top, and the kettle handle goes over one of them so it stays cool. A lid covers the lower door, and the width of the gap sets the heat. Master Huang Shufan builds a removable inner firebox with a gap between it and the body, so the firebox expands on its own and the stove does not crack. The kettle that sits on it is a clay shadiao: 250–500 ml under the 2021 standard, 300–500 ml under the 2023 regulation. The Japanese sencha stove, the ryoro, follows the same idea: unglazed white clay, about 24 cm tall, three "claws" for the bofura kettle, a draft window called fumon. For classes where open fire is not allowed, there are ryoro with a built-in 300 W hotplate. For the rest of the kit, see [chanoyu utensils](https://howtotea.me/teaware/by-region/japan-and-korea/chanoyu-dogu). Global Tea Hut distinguishes open braziers, where charcoal is piled on ash, from closed ones with a removable firebox: you fill it with charcoal, light it outside and carry it in. The best ash, in their experience, comes from burned rice paper. Working a Chaozhou stove Twenty minutes before lighting, soak the clay kettle in room-temperature water or it will crack. Light small pieces of charcoal on a gas ring until the edges glow red, then move them into the stove. Fan through the draft opening: the wider the gap, the hotter the fire. When the lid rattles, the water is boiling. To put the fire out, set the lid on top and close the draft. In an open brazier, charcoal goes in a ring with an unlit piece of white charcoal in the middle. The heat is strongest in the gaps between pieces: pack them too tight and the fire chokes, too loose and the charcoal is gone before the session ends. ## Alcohol burners Water comes to a boil slowly over an alcohol burner. By Stéphane Erler's measurement, a liter takes 15 minutes on an adjustable burner. So it is mostly used to keep water hot: at outdoor sessions Global Tea Hut boils one kettle on gas and keeps a second warm over alcohol. On a burner with a damper, fully open gives a large flame, half closed a small one, and the cap puts it out. Be careful with the fuel. Ethanol burns sootier than methanol, but methanol vapor is toxic, and denatured alcohol may contain about 10% methanol. Fill the burner about two thirds full and refill it only once it is out and cool: most burns happen during refilling, and an alcohol flame is nearly invisible in daylight. Use it in a ventilated room. ## Electric and gas In an electric kettle the element is submerged or pressed to the base, so little heat escapes: 80–90% efficiency. Gas manages 36–56% in tests, typically about 40%, though one study measured up to 70% on a small burner with a weak flame. An open-coil hotplate reaches 70% at best. In one home test induction scored 79% against 84% for an electric kettle, so across different trials the two trade places. Induction comes with a catch: the current is induced in the base, so the base must be flat and magnetic. Clay, glass, copper, aluminum and non-magnetic steel stay cold, and the cooktop may not detect a kettle that is too small. For a clay or glass kettle, use a ceramic glass hotplate or a steel adapter disc. To check a kettle, hold a magnet to the bottom; it should stick. If all you need is hot water, an electric kettle is the most economical choice. People choose charcoal for the ceremony and for the process itself. ## What people say about the taste of the water Huang Shufan holds that water in a clay kettle on charcoal is "clean, sweet and soft". Wu De of Global Tea Hut is sure that fine teas open up better over charcoal, and that old iron [tetsubin](https://howtotea.me/teaware/materials/metal) need a live fire. Erler, by contrast, uses a ceramic kettle on an alcohol burner for unroasted [oolongs](https://howtotea.me/teas/oolong) and [green tea](https://howtotea.me/teas/green): its water, he finds, is "lighter" than water from cast iron. These are all practitioners' impressions, with no blind testing. The chemistry is simpler. Temporary hardness drops out as scale in any boil, while permanent hardness (sulfates and chlorides) stays. What matters is the boiling, not the heat source. When Wu De mentions charcoal's "infrared energy", he adds that he knows of no scientific explanation for it. There is no strict pairing of tea and fuel. In Chaozhou, olive charcoal has traditionally been used for oolong, above all Fenghuang dancong. Wang Yingxin recommends water heated on it for Wuyi rock oolongs and aged sheng puer. ## Carbon monoxide This is the main argument against fire indoors. The Tokyo Fire Department ran a test[1](#fn:1): in a closed 6-tatami room (3.3 × 3.6 × 2.1 m) they burned 10 pieces of charcoal, 85 g each, in a brazier. In 50 minutes CO near the ceiling reached 700 ppm. Breathing that for 3–4 hours impairs consciousness. Opening the door brought the reading down, but not to the standard, which the 2012 report gives as 10 ppm; since April 2022 Japan's limit has been 6 ppm. A table in the same report includes a case in which everyone at a chado class was poisoned in a closed tea room. In China the craze for "weilu zhucha", boiling tea around a brazier at the table, led to a wave of poisonings: in one month China CDC counted more than 30 cases and 270 people harmed by non-industrial CO[2](#fn:2). The main risk factor is poor ventilation. An open window is no guarantee, since the gas has no color or smell. After severe poisoning, delayed encephalopathy can follow 2–60 days into an apparent recovery. So light the charcoal outdoors, ventilate the room and keep a CO detector. Global Tea Hut insists on this even with smokeless charcoal. ## Care Keep a clay kettle full of room-temperature water, so you don't have to wait 20 minutes for it to soak. You can rinse new charcoal under running water and dry it in the sun, picking out unfired pieces with shiny patches. Cap the alcohol burner, or the alcohol will evaporate. Unglazed ryoro and bofura are fragile. ## Common questions Does charcoal water taste better than electric kettle water? There are no blind comparisons. Practitioners, from a Chaozhou master to Wu De of Global Tea Hut, call it softer and livelier, but these are impressions, not blind tests. It is the boiling that lowers hardness, not the fuel: temporary hardness drops out as scale on any heat source. Can I heat water on charcoal in a closed room? No. Even smokeless charcoal gives off carbon monoxide, which has no color or smell. You need ventilation and a CO detector, and the brazier is best lit outdoors. China CDC names poor ventilation as the main risk factor in poisonings. Why will a clay kettle not heat on induction? Induction drives current into a magnetic base, so clay, glass, copper, aluminum and non-magnetic steel stay cold. If a magnet sticks to the bottom, the kettle will work. For clay, use a ceramic glass hotplate or a steel adapter disc. Notes 1. Tokyo Fire Department, K. Kaneko et al., "Verification of carbon monoxide poisoning cases," Safety Report no. 49, 2012: [pdf](https://www.tfd.metro.tokyo.lg.jp/content/safetyreport/000005897.pdf). Limit since 1 April 2022: [Japan's Ministry of Health](https://www.mhlw.go.jp/bunya/kenkou/seikatsu-eisei10/). [↩](#fnref1:1) 2. China CDC, "Indoor weilu zhucha: safety notice," 17 January 2024: [chinacdc.cn](https://www.chinacdc.cn/jkkp/zyjk/zdzs/202401/t20240117_301113.html). 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