Tea nerds: question about heating water for tea
January 11, 2011 7:58 PM   Subscribe

I'm just getting started drinking actual good loose tea. At the fancy-shmancy tea store they looked at me like I had two heads when I suggested microwaving the water to heat it for tea. The scoffed and said that microwaving "flattens the water molecules." This is crap, right? Heating is heating, no?
posted by spifl to Food & Drink (40 answers total) 9 users marked this as a favorite
Yes, it's crap.

Regardless of the physics behind it, prepare two servings of tea - one with "traditionally" heated water, another with microwaved water. Bring them to the store and ask them to sample the tea, identifying the heat source used for each. Draw your own conclusions.

Or, do what tastes best to you.
posted by HannoverFist at 8:03 PM on January 11, 2011 [2 favorites]

"Flattening the molecules" sounds like bunk, but microwaved hot water does have a noticeably funky taste if you normally boil it on a stovetop.
posted by oinopaponton at 8:04 PM on January 11, 2011 [11 favorites]

It doesn't do anything to the water molecules but it might change the oxygen content of the water, which apparently can change the flavour of the resulting tea. Boiling it in a jug or kettle then pouring it into the cup aerates the water, which you don't get from microwaving. Also the act of pouring over the leaves kind of stirs them up and helps the flavour come out. This is also why some people will say not to reboil the water, use fresh each time.

Tea definitely goes nasty if you microwave the whole thing once the milk is added, don't do that. But personally I don't notice a difference if I only use the microwave to heat the water then still pour it over the tea leaves, although I imagine the people at my tea shop would recoil in horror too. I also don't measure my tea but do it by eye *gasp*, they get hung up over weird things.
posted by shelleycat at 8:04 PM on January 11, 2011 [6 favorites]

I meant to type "pouring it into the pot" up there rather than into the cup, but pouring it over the tea leaves where ever they are is is the main point.
posted by shelleycat at 8:05 PM on January 11, 2011

If you are simply looking for a fast way to heat water I suggest getting an electric kettle. Mine seriously rocks.
posted by St. Alia of the Bunnies at 8:07 PM on January 11, 2011 [19 favorites]

I assume that it is crap, but as a tea drinking ponce I don't ever zap my water anyway. It's easier to get the water to the right temperature for whatever specific kind of tea you're brewing if you use a kettle, and then the action of pouring the water onto the leaves helps get everything swirling together and brewing nicely. If you don't clean your microwave regularly, it can also contribute unwanted bits of flavor into your water.

An electric kettle is good, but a plain stove top kind really only takes about 4-5 minutes to boil enough for a small pot of tea, and then when you get used to it, you can do things like count a certain number of seconds after bringing it to a boil before pouring it onto green tea leaves so you know it's right every time and you don't scald them. I suppose that works with an electric as well, but there's something about the whistle... It's a ritual thing, really.
posted by Mizu at 8:13 PM on January 11, 2011 [3 favorites]

Microwave ovens don't flatten water molecules, but they are capable of producing superheated water that can splash a lot or (scare quotes!) "explode" when you add something to it.

The Mythbusters video I linked used sugar, not tea, they found the effect only in distilled water rather than tap water, and they didn't think it would happen very often, but they still called the claim "confirmed".

If you're making tea with good, loose black tea, get an electric kettle with an automatic shutoff, use fresh cold water every time (twice boiled water has less oxygen, making for a "flatter" taste), pre-warm the pot, and bring the kettle to the pot so the boiling water goes over the leaves at the right temperature. Green tea needs very, very hot but not quite boiling water, so adjust accordingly.
posted by maudlin at 8:13 PM on January 11, 2011 [2 favorites]

Yes, it's crap. However, if you don't regularly clean your microwave or (god forbid) are using an office microwave, the water can definitely take on some interesting flavors and smells. Avoid that.

As for what to drink, see if you can get your hands on some Persian tea--obviously it'll be tough if you're in the US. Shahrzad is a good brand to try. That stuff is delicious.
posted by phunniemee at 8:15 PM on January 11, 2011

I think you're focusing on the wrong set of principles here. Okay, sure, science is science and hot water is hot water. But still, this is tea; there are rules.
posted by .kobayashi. at 8:22 PM on January 11, 2011 [14 favorites]

I HATE microwaved water for tea. It doesn't seem to boil correctly. The month I had no kettle and made do with the microwave and 'boiling' water tap at work was what made me realise the HUGE difference.
posted by geek anachronism at 8:28 PM on January 11, 2011

yes, it's not really what happens but I too know lots of people that say that tea made with microwaved water tastes different and worse. Get a kettle.
posted by GuyZero at 8:28 PM on January 11, 2011

I love my English Breakfast tea and think you can't go wrong with an electric kettle, especially since you can just boil a little at a time and have it fresh for each cup you need (my recommended way as I am convinced "old" water isn't as good). Tea fans can be tea snobs sometimes though, anything from insisting you drink the tea out of china to warming a teapot and brewing it that way. Whatever works and if you try both methods and can't taste a difference go with whatever works for you.

FYI some folks prepared a 5,000 word official document on how to make tea properly .. .. you could spend all day trying to figure out how to make it right. As for flattened water molecules my BS detector went off immediately ...
posted by AuroraSky at 8:29 PM on January 11, 2011

I have never noticed a difference.

posted by kyrademon at 8:35 PM on January 11, 2011 [2 favorites]

An Electric kettle is a necessity when you get into tea. It's quick, energy efficient, and to my tongue tastes better.
posted by parallax7d at 8:39 PM on January 11, 2011

Yay for using good leaves instead of crappy bagged stuff! However, there are people who would say "hell, use the damn Lipton bag, tea is tea, right?" You know they're wrong. So while heating is heating, yes, methods do matter, just like the tea itself matters. I wouldn't microwave a chicken breast and expect it to come out like one I cook in the oven.

I don't think flattening the molecules sounds like a real thing, but microwaved water rarely comes to a nice full rolling boil like kettle water does. The rolling boil adds more air in the mix, and without that, tea can taste flat or stale, even if it's piping hot.

Really what it comes down to for me is, if you're bothering to pay for decent tea, you may as well go with the better process.
posted by donnagirl at 8:40 PM on January 11, 2011 [3 favorites]

One thing to consider is that, in the microwave, the container usually gets heated, too. This would probably be mitigated by using a high-quality glass container (like a beaker), but for some reason, heating the water in a ceramic mug makes some mugs get hotter than the contained water.
posted by amtho at 8:46 PM on January 11, 2011

Also: I think the best temperature for *green* tea, at least, is 160-180 Fahrenheit - no boiling.

Here's a temperature guide, and here's another one that recommends 200F for black tea.
posted by amtho at 8:49 PM on January 11, 2011

If you microwave your water it can superheat, and then blammo. I didn't believe this till it happened once in an office where I worked: the cup has to be very smooth, with nothing to break the stasis of the superheated water till you touch the surface, and then all the bubbles that gradually surface during normal boiling surge out at once.
posted by zadcat at 8:57 PM on January 11, 2011

The molecular flattening thing is absolutely bunk. Microwaves do not ionize or put any electric charge or anything like that onto the molecules - the only thing that could change the shape of a molecule. Polar molecules physically oscillate in the alternating electric field the microwave produces and the heat thus generated is purely mechanical.

I think there could be something, to the true tea snob, to the issues of water not coming to a boil. I would argue, contrary to what is suggested above, that boiling de-gasses water, and it brings water to a precise, stable temperature, and all the established rules around "proper" tea-making are based on water heated by convection. Serious tea people are very precise about the state of the ingredients, what is added to what, how long the steep occurs, and so forth. Is it all (or at least at some point in the game) the equivalent of special audiophile speaker cables? I couldn't tell you.
posted by nanojath at 9:13 PM on January 11, 2011 [2 favorites]

Yeah, if you're heating water for teas that need water at something less than boiling (green tea, white teas, some tissanes, etc), it would probably be moderately hard to get a really exact temperature from the microwave. I have a nice electric kettle, but I've also used the stove top. Whatever works for you, really.

That said, I take everything they say at tea shops with a half a metric ton of salt ever since they tried to pass off the raw sugar as being more taste-free than regular old white sugar. Because, as we all know, molasses is entirely bereft of flavor.
posted by Kyol at 9:19 PM on January 11, 2011 [3 favorites]

I've never noticed a difference.

Aeration I can buy. Also steeping temperature and length of steeping time are the biggest determinants in how well the tea comes out. Swanky loose tea often comes with recommendations. If the microwaved water isn't reaching the high temps that dark black teas need, for example, I can imagine it coming out not as well.

posted by MillMan at 9:20 PM on January 11, 2011 [2 favorites]

Hot water is hot water.

Maybe it tastes different b/c...
* it absorbs odors from a dirty microwave? (clean the microwave)
* you're missing the aeration step by not pouring into the cup after heating? (use separate containers for heating/steeping)
* it's the wrong temp? (get a thermometer, then test various heating times to get the right temp)
* the microwaved water is actually more pure than the kettle water? (add metal impurities from the kettle to your water)

As others have mentioned, variations in steeping will have a much greater affect on flavor than how the water was heated.

I dislike using kettles b/c I'm only making one cup. Heating 8oz of water in a microwave for 1:45 gets it to just under boiling (for my specific microwave/cup combo, and starting temp of my kitchen tap).

Using a kettle takes longer, and results in a lot more water being heated than is actually being used. Why heat 4 cups of water when you're only drinking one cup? It's not like coffee where you can make a whole pot...
posted by jpeacock at 9:38 PM on January 11, 2011 [1 favorite]

Yes, get an electric kettle. It takes less time than a microwave.
posted by apricot at 9:51 PM on January 11, 2011

The issue with microwaved water is that it is often not heated fully. The top of the cup could be boiling, but underneath it is cooler. This will make poor tea.

If you were to heat, stir, heat, stir, etc. you could probably boil water fairly well in the microwave. I'll just stick to my electric kettle.
posted by Earl the Polliwog at 9:53 PM on January 11, 2011

I'm a giant tea snob. But yeah, microwaved water shouldn't be a problem- you'll be experimenting a lot to find a good temperature, though.

Me? I can tell what the temperature is by the sound of the metal creaking as my kettle expands and the bit of steam escaping from the spout. Do what works for you.

And generally, yeah, the biggest deal is temperature and length of steeping, the second part, being usually a lot shorter than people expect.
posted by yeloson at 10:50 PM on January 11, 2011

Came in to say what Earl the Polliwog said... microwaves often heat water unevenly so even when it looks like it's boiling not all the water is that temperature, which then affects the way the tea steeps.

Nthing an electric kettle for speed and convenience.
posted by SymphonyNumberNine at 3:12 AM on January 12, 2011

My grandparents managed the "exploding water in a microwaved cup of tea" trick, so it's certainly possible.

I suspect that the problem with heating water in a microwave is that for proper tea (made from black tea at least) you want to be pouring the boiling water straight onto the tea leaves. You can't easily do this with a mug or jug heated in the microwave: you risk either not heating it enough (just because it's started to bubble doesn't mean it's evenly heated all the way through) or too much and superheating the water.

Also, reaching into a microwave and pulling out a jug of boiling water sounds like it would be more risky to me (over a lifetime) than just using a kettle which is designed for the purpose.

Flattening the water molecules is just bunk, but it is possible that microwaving it changes the taste. Ordinary tap water contains a bunch of trace ingredients which affect the taste, it's certainly possible that microwaving (which preferentially dumps energy into certain molecular bonds) would act differently on those than heating in a kettle. Try a blind taste test: get a friend boil, then leave to cool cups of water by each method, including a non-heated control & then compare the taste youself.

(Personally, I can't tell the difference with just water, but I can tell if tea has been reheated in the microwave: I think the milk reacts when microwaved & changes in taste.)
posted by pharm at 3:47 AM on January 12, 2011

If you actually get the water to a rolling boil in the microwave, you should not have a problem.
posted by gjc at 4:26 AM on January 12, 2011

Going with jpeacock: microwaved water is likely to pick up funky smells from the microwave and fail to come to an actual rolling boil, both of which can potentially affect the taste of tea.
posted by valkyryn at 4:54 AM on January 12, 2011

Flattening the molecules makes no sense, but in my experience the made with microwaved water really does taste bad and off for some reason.
posted by Eshkol at 6:03 AM on January 12, 2011

tea, even
posted by Eshkol at 6:03 AM on January 12, 2011

I think the origin of your "flat molecules" is a mix-up of two different parts of a proper tea ritual.

Firstly, water that has been repeatedly boiled - for example, by filling a kettle and making several cups of tea from it over a day - is referred to as "tasting flat". This is apparently because there is less oxygen in the water. Of course, the molecules themselves are not flat. The word "flat" in this context means "less interesting", similar to flat cola. The molecules are the same shape as before, but some of them are no longer there. You can try this yourself: boil some water in a pan for a long time, cool it and drink it. It's unpleasant.

The problem with microwaving the water is nothing to do with this. Microwaving water introduces a completely separate tea sin, in which black tea is made with water that isn't completely 100% boiling. Boiling water properly in a microwave is difficult because of the risk (mentioned above) of being attacked by steam explosions when lifting out the mug. But, properly boiled water is necessary in order to get all the good bits out of the tea quickly, so you can remove the tea bag before the nasty bitter parts start dissolving too.

Use a kettle; get a rolling boil, use a little bit of the boiling water to warm the teapot, then throw that water out and start your tea making ritual properly.
posted by emilyw at 6:39 AM on January 12, 2011 [3 favorites]

I'm not science-y enough to know whether or not this is actually crap, but I can tell you that, especially with high quality loose teas, I can taste the difference between microwaved tea and not-microwaved tea. The 'waved tea has a distinctly bitter taste.

Really, if you're spending the dough & the time on nice tea, grab yourself an electric kettle. It won't take any longer, it will taste better, and it will add a lovely bit of ritual to the whole thing.
posted by AmandaA at 10:02 AM on January 12, 2011

I used to work in a tea shop similar to Teavana, and whenever someone spoke of microwaving tea I was always quick to condemn it. My reasoning for this was because often people would either 1.) Microwave the water the tea already inside the cup or 2.) Just boil the absolute shit out of the water because they could never really guess a correct time in the microwave.

Regardless of whether or not you're microwaving it, the most important factor is the temperature of the water when you put the infuser in the mug. Chances are if you're using a microwave it'll be boiling hot and you'll burn your tea instantly. The taste after burning leaves, for me anyway, is ungodly and so (with the exception of black and herbal teas) I can usually have bad tea when I microwave it.

If you're really into tea I'd spring for the UtiliTEA Kettle from Adagio. You can set the kettle to various temperatures depending on what tea you're having, insuring that the disgusting burnt taste of tea will never touch your precious lips again!

Oh, you know, just microwave it and let it set for a few minutes.
posted by _superconductor at 10:30 AM on January 12, 2011 [1 favorite]

I suspect "flattening the molecules" is someone's "science!" reinterpretation of "flat water" -- if you boil the water so long that the dissolved air all escapes, it tastes "flat".

I do use the microwave to boil water for tea. The important things are a clean microwave (as many have already said) and knowing exactly how long to heat it for, so you don't end up with superheated accidents or flat water. Kettles have a very convenient indicator of the right temperature -- boiling -- that microwaves don't.
posted by phliar at 2:30 PM on January 12, 2011

Microwaving water introduces a completely separate tea sin, in which black tea is made with water that isn't completely 100% boiling.

I used to subscribe to this theory until the day I realised that when I lived in Idaho at 4500 feet, the boiling point of water was rather lower than 100 C (212 F), but I still liked the taste of the tea. I now plan on 95 C.
posted by phliar at 2:36 PM on January 12, 2011

Yes, it's crap, heating is heating, but boil the water. Please. It really does make a difference to the way tea brews, and tastes.
posted by Decani at 2:53 PM on January 12, 2011

the boiling point of water was rather lower than 100 C (212 F), but I still liked the taste of the tea. I now plan on 95 C.
posted by phliar at 10:36 PM on January 12

You would like it better at 100.
posted by Decani at 2:54 PM on January 12, 2011

Yes, the microwave is fine. The only caveats are that it takes longer than a proper electric kettle, the cup itself can get dangerously hot, and the water may super heat but not boil which can lead to a steam explosion when you put in your infuser. FWIW, the super heating problem is easily fixed by adding a toothpick to the water which will add nucleation sites to facilitate boiling.
posted by chairface at 11:57 AM on January 13, 2011

You would like it better at 100.

Perhaps I wasn't clear: if you don't live at sea level, you cannot heat water to 100 C without using a pressure cooker.
posted by phliar at 5:16 PM on January 13, 2011

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