|A tea thermometer in action
(Photo used with permission)
Setting aside heat’s effects on the growing of tea plants (Camellia Sinensis), I want to focus on the impact of tea temperature on the flavor of the resulting liquid. There are actually two general categories here: steeping effects and drinking effects.
What you start out with is not always what you end up with. It can be frustrating, but that’s physics pure and simple. Heat means activity. Those little water molecules get to doing quite a dance when they are hot. Well, just as most people can’t dance all night, neither can those water molecules. Sooner or later they slow down, and that means the water gets cooler. So your initial water temperature is not what you end up with. How much variation there is depends on your starting temperature, steeping time, and the temperature of the air where you’re doing the steeping.
Ending water temperature (what the temp is after steeping) can be 20, 30, 40 or more degrees cooler than when the water was first heated. My experience (not a scientific study here, just personal observation) is that water cools about 10-15 degrees per 45 seconds. Also, a closed steeping vessel (lidded teapot, gaiwan, cup, glass, etc.) will cool more slowly. Covering the steeping vessel with something such as a cozy will also retard cooling. If you are using a Yixing clay teapot, pouring some of the hot water over the outside of it after filling it will also help.
Why bother? Simple. A truer steep. Vendors provide steeping instructions to help you get the best from their teas. But there are other factors beyond their control, and how well you are able to maintain an optimum steeping temperature is one of them. While cooler water prevents scorching, very hot water can extract more flavor, but you need to keep the infusion time very short (10 or 15 seconds for the initial steep).
At some point, you learn that some teas prepared in very hot water taste a better when they are let stand a minute or two to cool slightly. Tea flavor is a pretty complex thing. There is the aroma, which helps convey flavor since smell and taste perceivers are in close proximity in your head. It’s one of the reasons that professional tea tasters slurp the tea into their mouths — they bring in air with the tea and force the fragrance up through their nose. Some tea flavors hit your tongue right away when you sip. Others emerge as you swallow and bits linger, stimulating your tastebuds. If you sip the tea when it’s piping hot, you risk scalding those tastebuds and thus not being able to taste the tea at all. As the tea cools, you have less chance of tongue scalding but also you get to perceive the tea flavors more since some are more pronounced in a cooler cup and you can keep that cooler liquid in your mouth a second or two longer so the flavors have a better chance to impact your tongue. If the tea cools too much, bitterness can come out, especially for black teas that tend to be steeped longer.
How to Assure Proper Temperature
You have options here:
- A tea thermometer — This is probably the most reliable method but may seem a bit too much like a scientific experiment for some tea drinkers who want a more aesthetic tea time.
- An electric kettle — The level of precision depends on the kettle and again lacks that aesthetic element. Plus somehow this just seems to technical. However, it tends to be very practical and also means you can heat water in an area where water and electricity are available but not a stove.
- Watch the water — Ah! Here’s that aesthetic element, where you watch the water begin to dance as it heats. Bubbles will rise to the surface. How many and how frequently they rise is an indicator or water temp. To use this method, though, you need to count fast or have quite a bit of experience watching the water and then determining the temperature.
With all this in mind, I encourage you to let the liquid cool slightly (about 30-60 seconds) before sipping. However, you may have to experiment a little to see what works best for you.