Why You Should Never Microwave Tea—Plus the Right Way to Brew It

A better cup awaits those who embrace the kettle over the microwave (the laws of physics agree).


Victoria Jempty

A not-earth-shattering fact: Tea is mostly water. But humor me for a moment, because the implications of this statement are heavy. It connotes the importance of how you choose to heat your water to make tea—something that will determine whether your mug is top-notch or completely tasteless. And while using a microwave to heat tea water is the easy way, it is anything but the best method. Why look past the microwave? There are so many reasons.

Teas Require Drastically Different Brewing Temperatures

Many times, microwaving a mug heats the water way too much. This, in turn, makes lifting it from the microwave a task that can come with finger-burning and potential spilling of scalding water. Additionally, when the water gets too hot, you'll have to wait longer to drink your fully-steeped tea—tea that won't be brewed correctly.

Why? Because different teas require different water temperatures. Green tea (including matcha) and white tea should be steeped between 170 and 180 degrees. Black, oolong, rooibos, and herbal teas should be hotter-200 degrees or hotter. Shooting for the right temperature with a microwave is like reaching around in the dark. You have no way of knowing. With an electric tea kettle that has settings for each tea style or a built-in thermometer, all it takes is the push of a button.

Even without temperature settings, a tea kettle that you can hear heating up gives you a chance to estimate the temperature. Listening to the rising sound, you can hear your tea water simmering and roiling up to a boil. If you're brewing green or white tea, pour from the kettle before it reaches a full boil, that way you can pin the 170 to 180 degree range. As you use your kettle more, you'll come to know when the water is ready just by listening.

If you want to measure the water's temperature, you can use a kitchen thermometer. Doing so a few times might help you know when, as you listen, water reaches target temperatures.

The precise temperature might not matter to you. Still, whether or not you have a special kettle or another way to measure temperature, you should make sure you're in the right neighborhood—especially if you're buying better teas. Loose-leaf tea won't be worth the investment if you're microwaving water. The flavor benefits of loose-leaf and better-quality bagged teas are more fully extracted by steeping at the right temperature.

Microwaving Tea Goes Against the Laws of Physics

Speaking of flavor benefits, there is actual scientific research to support the notion that microwaving water to brew tea is just...incredibly wrong. One study conducted by researchers at the University of Electronic Science and Technology of China researched how heating liquid works in a microwave. It turns out that the electric field that acts as a warming source in the appliance causes the water to end up at different temperatures at the top and bottom of your mug. And a good cup of tea is about achieving a uniform temperature throughout your mug.

Conversely, when warming a liquid like water on the stove or within a kettle, the heating source warms the container from below. This is when a process called convection occurs, which results in a perfectly uniform temperature throughout the kettle.

Unfortunately, if you're heating a mug of water in the microwave for 90 seconds (like the researchers did), the device's electric field heats it from all angles, not just from below. The result? The top part of the mug's water may be boiling, while the bottom is far from a boiling point. "Because the entire glass itself is also warming up, the convection process does not occur, and the liquid at the top of the container ends up being much hotter than the liquid at the bottom," states the study. Translation? A crummy cup of tea.

Tea Should Be Relaxing, Not Rushed

Next, there are the mental benefits of skipping the microwave. Just like with the Swedish coffee break tradition known as Fika, drinking tea gives pause. It is a break in the relentless momentum of the day. It's a time to immerse yourself in a calm moment; the chance to slow down. Drinking tea might come with your own personal traditions-perhaps a certain cup or a certain pot. Many tea traditions are deeply rooted in time. Microwaving tea water feels out of step with these traditions and the relaxed, old-school nature of tea. Tea is best when it's slow and deliberate. Instead, microwaving speeds up tea, cheats the system, and removes it from its origins.

Across the world, there are various teas steeped in a variety of ways. Some, like pu-erh, even have a rinsing ceremony when enjoyed formally. This includes pouring hot tea water over the surface of the closed clay pot, warming the pot, thus better preparing it for hot water. There is also the rinsing of tea itself—where hot water is poured over tea very briefly and then discarded, opening up the tea for the actual steeping. Matcha requires careful whisking to properly prepare. Tea traditions vary, and it's important not to ignore them.

Yet, one thing remains universal: For maximum enjoyment of tea, skip the microwave.

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