Don't Use Your Microwave To Make Tea

If your kettle has just carked it, it can be tempting to use the microwave to quickly heat up some water to make tea. If you do that, though, you're quite likely to end up with a terrible tasting cuppa. Here's why that happens.

Photo: chumsdock

Slate's Nadia Arumugam explains why microwaving water doesn't result in anywhere near as satisfying a cup of tea as using a kettle. It comes down to a matter of convection:

Microwaves don’t heat water evenly, so the boiling process is difficult to control. 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.

The result when you drop a teabag or infuse some leaves in that water is that you get an unpredictable and terribly uneven chemical reaction, which can lead to a terrible tasting cup of tea. This gets back to a concept we've covered at Lifehacker previously, which is that tea works best when it is introduced to water which is actually boiling.

The one exception to this appears to be green tea, which can work with lower temperatures to produce a pleasing taste. But for other types of tea, if the kettle is kaput, stick a saucepan on the stove, and take your time. A good cup of tea is worth it.

Food Explainer: Why Does Microwaving Water Result in Such Lousy Tea?


Comments

    Well the solutions appears to be a no-brainer then. Stir the cup of water to ensure even temperature distribution? Then add the tea.

    Obviously you can't have it at a rolling boil and remove it from the microwave, but hey, it would make f all difference since the kettle isn't at a rolling boil still when most people pour it.

    Last edited 05/06/13 2:46 pm

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      The point is (without republishing the entire linked article) that water that appears to be "boiling" in the kettle may still be well below 100 degrees; stirring it would equalise the temperature, but in doing so bring it even further down.

        Tea should be infused with water that is around the 80 degree mark, not 100 (boiling). Why do you think kettles are now made with different heating options for tea and coffee?

          I thought tea was supposed to be made at 98 degrees.

          Depends entirely on the type of tea. Most green teas work best at 80, most Oolongs between 85-95, and most black teas around 95-100.

        Well, for microwaves, not necessarily. According to the article there are hotter and colder pockets of water in the cup. Stirring would mean it goes up in some places, while simultaneously going down in others. Doing so only brings the temperature down depending on which pocket you of water you've based the temperature measurement on to begin with, it could very well go up.

        Also I'm not sure how this changed to kettle's? I thought we were talking about microwaving the water. I would assume that you would not need to stir water poured from a kettle to equalize the temperature, as this would likely occur automatically when filling the cup / teapot.

    More importantly is the superheating of water in the microwave, which occurs due to insufficient nucleation points in your cup. As soon as you disturb your cup of hot water, it can instantly boil, causing injury.

    http://www.youtube.com/watch?v=1_OXM4mr_i0

    I think this is more important that a bad cuppa, which can be theoretically solved by simply stirring the water to a consistent temperature.

      Was going to say something about that. Don't microwave water, guys, srsly. Third- degree burns to the face are not pleasant.

    WTF?
    OK. Let's look at some facts.
    1: Microwaves have a rotating plate. The chance of a single point in the water to always be at the point of a standing wave is next to nix.
    2: Water is an excellent conductor of heat (Hence why people use it as a coolant in cars and computers)

    The likelyhood that some point in your water is going to have such a wildly different temperature to some other point in your water is inconceivable. (The act of pulling a mug/pot of water out of a microwave will stir the water and even the temperature out).

    This is just the most silly argument/article I've seen in a while.

      Ok, having had a quick read of the actual article, the main point is that when you heat water in the microwave, it can exhibit signs of "boiling" whilst still being well below 100 degrees (eg. a few bubbles at the surface, water vapour coming up from the mug, etc). They're suggesting that people tend to take the water out of the microwave at this stage and make the tea when the water isn't hot enough for proper infusing.

      Last edited 05/06/13 3:24 pm

      I stand to be corrected on this, but I think what you've said is not entirely true. Worth reading an article such as this from UNSW:

      http://www.animations.physics.unsw.edu.au/jw/superheating.htm

      Basically, because (1) microwaves can heat water without forming bubbles, which is required to distribute the heat by converting the water to vapour; and (2) because microwaves containers tend to have very smooth sides, and so don't form bubbles as readily given (1), the temperature of water in said container can vary wildly.

      As you say, water is an excellent conductor of heat, assuming it is able to "nucleate" (i.e. form bubbles to move the heat around. Without nucleation (I'm not a scientist, but I believe this is called departure from nucleate boiling (DNB), water can heat unevenly and exist at a temperature above its normal vapour point.

      This is actually very visible with tea bags. If you microwave the water and dunk the tea, the water around the bag "sizzles" as the superheated parts make contact with air. This can happen even if you leave the water to stand for a while - the heat is trapped in pockets with no way to form bubbles that distribute the heat.

        Agree with what you are saying to a "small" point.

        Grab a mug of water out of a microwave without having an impact on overall temperature.

        I suppose the original article could hold true in sterile lab conditions.

        But you are relying on a perfectly clean mug with no rough surfaces. (/me checks his mugs. Clean enough to drink out of. Hardly 'smooth')

        As for water being trapped in 'pockets of heat'? That is not possible without some form of insulator. Heat will leach, and leach quickly, to surrounding water.

        So.. If you had a perfect lab condition. A stable cup of water, with perfectly smooth sides, and put it in a microwave that doesn't move, and then immediately after heating (at high power, so you don't have time for the cooler water to absorb energy from the higher state energy water. ie. hotter) drop a teabag in, without moving the cup, then yes, you would get uneven temperatures across a teabag.

        Otherwise, as suggested by dcheetham, I think it's more likely that a person doesn't heat the water enough (Possibly out of fear of the story of exploding water, which is unlikely. Look up likelyhood of that. It's not as often as you'd think), and then putting a teabag into 'warmish' water. And yes, that tastes terrible.

        If it worries you that much, put a wooden paddlepop stick (or whatever the non-trademark name is) into the water and heat in microwave for 2 minutes. It'll boil.

    Why not just use the stove top?

      This is the internet. Your kind of logic has no power here.

    For tea-making science, try the Royal Society of Chemistry.

    http://www.rsc.org/pdf/pressoffice/2003/tea.pdf

    What a bunch of Pompous crap, especially the majority of the "discussions". I've been making Tea for at least 25 years in a Microwave and it's no different than having boiled the water in any other way.

    Last edited 05/06/13 10:13 pm

    If making tea with microwaves causes such complex discussion it's understandable why "climate change" (barf) leads to death threats!

    Really? I mean seriously? All this talk over heating up some water in the microwave? Can I just add - who gives a crap! Potato potarto. End of. Weiros.

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