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.