As you probably know, different kinds of tea need to be steeped at different temperatures to ensure you are getting the best flavour out of your tea. This is particularly true of delicate whole-leaf green teas which may be most optimally steeped at temperatures as low as 70°C (155°F). But how do you know when to stop your kettle at a lower temperature than boiling? There are of course temperature-controlled kettles out there, but if all you have is a kettle or a pot in your kitchen then you can use the traditional Chinese methods of determining water temperature by paying close attention to the way the water changes as it boils.
This method has been used for hundreds of years by the Chinese for cooking and for steeping tea. As an example, Cai Xiang (蔡襄, 1012-1067) – successful politician, Song Dynasty calligrapher, and expert in tea – wrote a famous book called the Record of Tea (茶錄) in 1049. In it he wrote about many important tea topics, and includes a reference to the use of shrimp eyes, crab eyes, fish eyes, and string of pearls for use in determine the temperature of boiling water. These different stages of water boiling are described below:
Shrimp Eyes (虾眼)
The first small bubbles – about the size of a shrimp’s eyes – start to appear at the bottom of the water. The temperature has now just broken about 70°C (155°F). This lower temperature is perfect to bring out the flavour of delicate teas without “burning” the leaves and to avoid bringing out the bitterness. Use it for very fine green teas, such as Longjin (龙井), Biluochun (碧螺春), or Japanese Sencha (煎茶).
Crab Eyes (蟹眼)
The bubbles grow larger to a “crab eye” size, and the first small wisps of steam will start to be visible from the top of the water. The temperature is now around 80°C (175°F), which is great for white teas like Silver Needle (銀針), a some green teas like Gunpowder tea (珠茶), and more delicate oolong teas such as Oriental Beauty (东方美人) .
Fish Eyes (鱼眼)
Bubbles the size of a fish’ eye start to appear and start to rise to the top. If you’re using a kettle, this will be the first time you’ll be able to hear it making noises. The water temperature is now around 85°C (185°F) so take the kettle off now for most oolong teas: Dongding Ooolong (冻顶乌龙), High-Mountain Oolong (高山乌龙), or Qilan (奇兰). It’s also good for black teas that aren’t fully oxidized This is the absolutely hottest temperature you should steep any green tea, even the cheap stuff you picked up in Chinatown.
String of Pearls (连珠)
A steady stream of bubbles forms that look like a string of pearls on a string. The temperature is now between about 90-95°C (195–205°F). This temperature is suitable for aged or ripe Pu’erh teas (陳年普洱), many whole-leaf black teas such as Dianhong (滇紅) and Keemun (祁门红), and heartier Oolongs like Dahong Pao (大红袍) or “Iron Goddess” Tieguanyin (铁观音).
Raging Torrent (翻腾) (騰波鼓浪)
The “rolling boil” in English, the temperature has now reached 100°C (212°F). This temperature right for strong black teas like Lapsan Souchong (正山小种), Ceylon, Darjeeling, and your everyday “builders” tea in teabags. It’s also right for tisanes (herbal “tea”).
Hopefully this post gives you an easy cheat sheet to help you get the right tea temperature for a given tea. With a little bit of practice this time-tested method will allow you to get the right temperature for your water and help you get the most out of your tea.
Update: the folks over at Más Que Té have translated this article into Spanish! Check it out: Ojos de pez en tu “kettle”: métodos chinos para medir la temperatura del agua.