The temperature of your water will have a noticeable effect on the flavor of your tea. In general, back teas, pu-erh teas and more oxidized oolongs will take higher temperatures. Green, white, and yellow teas, or teas with fresh and delicate flavors, will tend to take lower temperatures.

The easiest way to get the temperature of your water just rights is with a kettle that measures the temperature for you – some will even stop heating automatically once your desired temperature is reached. Alternatively, a thermometer that can sit in the water will do. If you’re using a thermometer after you’ve poured the water into a cup, remember to listen to the water while it’s being heated. The sounds will go through regular stages, and this is a good way to remember when to stop the heating next time.

If you don’t have a kettle that measures the temperature, or a suitable thermometer, there are two or three simple ways to get the correct temperature. They all involve brining water to a boil and then cooling it to your desired temperature.

One way is to add cool water to boiling water. That may seem strange, but it’s a very handy technique. It’s also good if you’ve accidentally let your water come to a boil, and want to cool it quickly. The purifying action of heated water is not changed by adding cool water to hot water. Water at 80°C kills bacteria whether or not all the water has been heated to 80°C, or some water has been heated to 100° and some has been added cold.

Here's a rough guideline, based on 150ml of water. To cool 150ml of boiling water to 95°, just add about 10ml of room temperature water. If you’re using positively cold water, use a little less than we’re recommending here. To bring boiling water to 85-90°, add about 30ml of room temperature water, or roughly one fifth of the volume that you already have. For 80-85°, try up to 45ml of room temperature water, or a little less than one third of the volume that you already have. For 70-75°, it can take adding up to one half of the volume you already have.

Another technique is simply to wait. It only takes about a minute for boiling water to come down to 95°, and roughly 2-3 minutes will typically be enough to reach 90° for a pot with up to a half liter of water. 4-6 minutes should get you to 80°, and 7-10 minutes should get you to 70°. Keep in mind that smaller quantities of water will cool more quickly. The less water that you boil, the less amount of time it takes.

Finally, pouring water into an unwarmed container will also take a few degrees off. We don’t find this such a handy technique, but it’s good to keep in mind when letting boiled water cool, because your cup or mug may do a little extra work for you.

We’d like to add, though, that not knowing the temperature precisely can be a good thing, since it ensures that you rely on your own taste for the temperature that gives the flavor you prefer!