Why Microwaving Water for Tea Is a Bad Idea

Apparently there are a lot of things us novice tea makers are doing wrong. A big one is using the microwave to heat up our water

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Making tea might seem pretty easy; you just heat up some water and add some tea leaves. But apparently there are a lot of things us novice tea makers are doing wrong. A big one is using the microwave to heat up our water.

It seems like no big deal. Tea requires hot water. Microwaves make things hot. What’s the problem?

It turns out that tea requires certain types of hot water. That is, water at a certain temperature. Green tea, for example, should be steeped at 176º F; herbal tea requires 210º F. When you stick your mug in the microwave, you have no idea how hot your water is. Tea kettles, on the other hand, are designed to heat tea to 212º F, according to Slate.

There are a lot of other theories about why nuking your mug isn’t the best. Slate says that the microwave will result in unevenly hot water:

Microwave ovens shoot tiny waves into the liquid at random locations, causing the water molecules at those points to vibrate rapidly. If the water isn’t heated for long enough, the result is isolated pockets of very hot or boiling water amid a larger body of water that’s cooler. Such water may misleadingly exhibit signs of boiling despite not being a uniform 212 degrees. For instance, what appears to be steam rising from a mug of microwaved water is only moist vapor evaporating off the water’s surface and condensing into mist on contact with cooler air—it’s the same principle that makes our breath visible on frigid days.

But Lifehacker says that this isn’t quite right:

That’s not true—after all, microwave wavelengths are about 4-inches, so unless you have a really huge teacup, you’re getting pretty even heating, especially if you remember to put it on the edge of the carousel, so we don’t think that’s much of a problem, especially if you stir after heating.

The two do agree though, that the right temperature of water is really important. Overheating your water can make your tea taste bitter and weird, says Slate. But those without a kettle shouldn’t despair just yet: as long as you’re willing to drink only green tea, the microwave is the way to go.


More from Smithsonian.com:

Two for Tea
Can You Make Tea Out of Coffee?