Boiled water: difference in microwave vs stove

The holidays are a chance to come together, to reminisce, and to argue like crazy, right?

At our holiday gathering, we argued over whether there was a discernable difference in the flavor of water boiled in the microwave vs the stove. I was outnumbered 3 to 1 in my assertion that there couldn’t possibly be a difference.

And I was going to prove it. I prepared 2 cups of boiled water. One heated in the conventional manner in a stainless steel teapot on the stove. The other heated in a ceramic mug in the microwave. Both heated until boiling and allowed to boil for about 1 minute. Then, I poured the water from each source into a ceramic teacup (the teacups were identical). The water was allowed to cool for about 5 minutes and then everybody tasted it. Ha ha, I thought, now I’ll show these suckers who’s boss.

Unbelievably, each of them guessed correctly (we recorded responses in a secret ballot). This prompted me to take a sip of each and was astounded when I too discerned a difference. The stove boiled water tasted, I dunno, like hot water, while the nuked sample had a SLIGHT off taste.

I appreciate that there are flaws in the experimental design (operational-water was heated in metal on the stove, ceramic in the microwave. Statistical: by dumb luck, one out of 8 trials would come out this way even if there were no differences in the water)but does anybody think there may be something to this?

All I could come up with is a somewhat weak mechanism. Along the lines of oxidation of impurities in the water heated in the microwave secondary to superheating.

It might have something to do with the amount of dissolved gases in the water. It takes longer, usually, to heat water on the stove, so I could see more oxygen coming out of solution.

It might also have to do with temperature -- if the microwave doesn't heat the water evenly, the water might appear to boil but might not actually be as hot as the water on the stove.

While I don't usually have any complaints about microwaved water for tea, I do know that when I use a hot water spigot (from a coffee machine or water cooler), the tea always tastes sort of flat.

My grandpa drove my grandma crazy for years by claiming that the newfangled Amana Radarange didn’t get his water hot enough for his instant coffee, and besides, it tasted funny. She pooh-poohed him and went right ahead making instant coffee for herself with the microwave. He retaliated by boiling exactly one (1) cup of water in the teakettle for HIS coffee, which REALLY drove her nuts.

Then, many years later, when I grew up and had my own microwave and my own stove and my own teakettle and my own little jar of instant coffee, I came to the conclusion that he had been absolutely right. Sorry, Grandpa.

And after many years, I have finally convinced the Better Half that I would really prefer my Lipton teabag to be brewed in boiling water from the teakettle, not half-heartedly steeped in merely hot water from the microwave. It just isn’t the same. You pour boiling water from the teakettle on a teabag and whoosh! lovely brown tea starts flowing out of the sides of the teabag. You pour microwave hot water on a teabag and it just sits there, very slowly leaking brown stuff into the water. Or worse, put the teabag in the cup BEFORE you put it in the microwave. Ick.

And yes, I am a fanatic, thank you for asking.

But I think this happens rapidly when you boil water. The double whammy of low solubility of air in very hot water and the action of boiling are sure to degas the water in both instances

To avoid uneven heating, I allowed the water to reach the boiling point and allowed it to continue boiling for one minute. I reasoned that the action of boiling should more or less thououghly stir the water

Here’s a somewhat related link regarding boiling water in the microwave. There might be a relevant bit of wisdom in it:

Just a WAG, but could the taste difference be due to the containers? I would guess that something comes off the steel when you boil the water.

I’ve noticed that anything put into my microwave tastes like fish recently. I finally stuck my head in to take a look and the top of the microwave is coated with ex-fish protein (exploding fillets, I guess.) So, now I have yet another thing to clean up.

Perhaps there is something in the microwave that funks up your water?

Perhaps the off taste of the microwaved water comes from whatever you last microwaved in there that splattered even a tad. You notice how, if you microwave popcorn, the microwave tends to smell like popcorn for quite a while afterwards? Perhaps that smell got into the water through the stirring action of the boil, as compared to the stovetop water, which had the same air that everyone was breathing circulating through it.

If this makes no sense at all, please forgive me. But it is 2 in the morning.

I just pour the water in an electric kettle and plug it in the wall and it always tastes the same.
Don’t you have electric kettles in the US?
Actually I think it takes longer to boil the water in the microwave anyways.

You forgot to stir it. Water in the microwave must be stirred once it is boiled.

Water on the stove is stirred by convection or whatever of the heat.

I let it boil for a minute. This mixes it well.

If this had been my microwave, splattered food would be a likely cause. However, this was my Mom’s microwave and this lady knows the meaning of clean.

Does anyone know how hot water superheated in a microwave could get?

“I just pour the water in an electric kettle and plug it in the wall and it always tastes the same. Don’t you have electric kettles in the US?”

Not the kind of electric kettle you are thinking of. We do have 110 volt models but those I have seen take forever to boil water. They are nothing like the electric kettles used in the U.K. or on the Continent that are faster than a microwave.

“I let it boil for a minute. This mixes it well.”

Not in a microwave. My microwave manual, which I read, says to stir liquids after microwaving.

How could that be? Steam bubbles form in the solution (or on a flaw in the container wall-whatever, they nucleate) and then go, in my microwave, up. They must shove past thick-headed water molecules that haven’t the good sense to vaporize. All that pushing and shoving has got to mix things up.

As to why the mike manual says you need to mix, I dunno. My car’s owner’s manual says to change the oil every 3-5K miles. I’m at 50K, no oil changes and no problems. I guess the manuals aren’t always right

Disclaimer: the part of my last post discussing oil changes was a joke