Posted by: tanstaafl.
Microwave Oven Safety - 20/07/2006 23:20
An acquaintance tried to convince me that microwave ovens caused unhealthy changes in the food that they heat. Maybe so. Maybe not.
But when he told me that plants watered with microwaved water would not grow, I became very skeptical. He invited me to perform the simple experiment of growing two plants from the same packet of seeds, one of them watered with water boiled on a conventional stove, the other with water heated by a microwave oven. Of course the water is allowed to cool before being applied to the plants.
I read of one experiment that supports this idea, but it was not scientifically run, no double-blind (or even single blind) methodology, and was a 6th grade science project. Perhaps microwaving leached contaminants out of the plastic container, or perhaps contaminants already present in the water might have been adversely affected by microwaves, or perhaps the experiment was never run at all and the results were made up, or ??
Does anybody have any insight into this idea? I remain highly skeptical, but am tempted to repeat the experiment myself.
tanstaafl.
Posted by: wfaulk
Re: Microwave Oven Safety - 21/07/2006 00:40
While it's vaguely possible that microwaves could damage foods in ways we don't know about yet, the notion that water can be changed by a microwave is complete hogwash. There are very few things that can be done to water. You can contaminate it or decontaminate it. You can change it from ice to water to steam. You can turn it into oxygen and hydrogen. That's it.
I'd guess that, assuming that the experiment wasn't contaminated in some way, which I'm inclined to say it was, the microwave likely had an effect on preexisting contaminants in the water. Given how much easier it is to boil water in a microwave than on a stove, I bet the contaminants were simply more concentrated in the microwaved water. A good way to test that would be to start with distilled water.
I also bet the same vessel was not used to contain both doses of water. The only thing I can think of that can perform on the stovetop and the microwave would be Corningware, but I bet metal was used on the stovetop and either glass or plastic in the microwave.
I'd try it, but I'm terrible at growing plants, and, well, I've got better things to do than spend that much time disproving crackpot theories.
Posted by: sein
Re: Microwave Oven Safety - 21/07/2006 10:04
I don't have any real idea whether Microwaves are actually dangerous.
But I do think they can alter the taste of food in a very subtle way. I really think a glass of water that has been Microwaved for a few seconds tastes different to water that has been in the Kettle for a few seconds.
I haven't met anyone who agrees with me yet. Am I crazy?
During Ramadan when we're fasting we get up before dawn for a bit of breakfast that will see us through the day. In the winter mornings the water from the tap is very cold, so this is how I've been testing my theory
Posted by: andy
Re: Microwave Oven Safety - 21/07/2006 12:59
I find the microwave most useful for steaming veg (in one of those microwave steamers) and making porrige.
A combined microwave/convection oven is great for jacket potatoes. Ours does convincing jacket potatoes in 30 minutes, nice and crispy because it gives the potatoes a blast with the microwave while it waits for the oven side to walm up and crispy them off.
Posted by: tahir
Re: Microwave Oven Safety - 21/07/2006 13:07
I do miss our old combi, used to be great for jackets, got a dodgy sanyo now, crap at jackets.
Posted by: wfaulk
Re: Microwave Oven Safety - 21/07/2006 13:09
Microwaves are looked down upon because they do a lousy job cooking a great many things, especially meats, which is one of the things they were initially marketed for. Remember when they advertised that you could cook a turkey or a roast in much less time? For thick things they work incredibly poorly since they largely can't heat things much past the boiling point of water (water is a large portion of the molecules in food that microwaves can successfully heat) and they only penetrate the meat by a few inches. That means that it's possible to cook a steak, but cooking a roast means you'd have to rely on intra-food conduction to cook the center, and since that sort of conduction takes a long time during which you have to continue pushing heat into the food, the utility of using a microwave in the first place is lost.
At the same time, you cannot form any sort of browning on a steak due to the low temperatures involved, and that's, at best, unappealing, and, at worst, just tastes lousy. Also, since the microwaves do penetrate beyond the surface somewhat, you have a hard time getting the outside done while leaving the inside medium-rare.
Also, and I don't have much to back this up, my personal experience is that microwaves make meat rubbery.
But they're great for reheating, as you seldom want to reheat past 212F/100C anyway.
As to your points: You must like rubbery eggs. I've had microwaved scrambled eggs and they're terrible. Maybe you add a lot of milk or cream? I have no experience with kippers at all, but they're thin and require low temperature cooking, so I can see how that might work well. And, you're right; it's hardly difficult to boil some water on the stove, and the microwave might end up cooking the egg via the microwaves instead of from the conduction of the boiling water, which probably wouldn't work well.
Posted by: tanstaafl.
Re: Microwave Oven Safety - 21/07/2006 15:22
cooking a roast means you'd have to rely on intra-food conduction to cook the center, and since that sort of conduction takes a long time during which you have to continue pushing heat into the food, the utility of using a microwave in the first place is lost.
I'm glad to see you are not perpetuating the [erroneous] myth that microwave ovens cook "...from the inside out."
But, if a mocrowave oven has to "...rely on intra-food conduction to cook the center...", then what does a conventional oven rely on? Seems to me it heats the outside, just like a microwave oven, and the heat has to migrate towards the center the same way.
Perhaps it is a function of the higher external temperatures provided by a conventional oven?
tanstaafl.
Posted by: wfaulk
Re: Microwave Oven Safety - 21/07/2006 15:48
My point is that you have to apply heat for the same amount of time (if not longer due to the lower temperatures that can be achieved by a microwave), so why waste your time with the microwave in the first place? It's probably going to end up taking just as long and using more energy, and the lack of the high temperatures on the outside or any radiative heating means that you aren't going to get any tasty browning. (Plus my anecdotal rubberiness factor.)
On the other hand, there have been times in history when browned meat was found to be gauche, which is the history behind wrapping a filet in bacon; originally it would have been some other cheap meat wrapped around the entire tenderloin roast and discarded (to the servants, most likely) before serving.
There are other concerns, too, like the fact that it's hard to control heating in a microwave, since it there is only one power (that can be cycled on and off on lower power settings on your micorwave oven) and the heat generated depends largely on the specific interactions with the material in the oven.
Posted by: altman
Re: Microwave Oven Safety - 21/07/2006 19:38
Zandr was telling me about a rather expensive practical joke involving buying heavy water (you can get it somewhere online, I hear) and making icecubes that sink in normal water....
Of course, as the heavy icecubes melt, they'll then float on the heavy water and start floating off the bottom of the glass. I think.
Hugo
Posted by: tfabris
Re: Microwave Oven Safety - 22/07/2006 15:53
Interesting! I didn't know such a kind of microwave existed.
Posted by: adavidw
Re: Microwave Oven Safety - 24/07/2006 05:34
I've got one. $99 at Costco. It works wonders for things like melting or defrosting. A traditional microwave at a low setting will cook the outsides of things while the inside is still frozen because even though it might only be powered for 2 out of every ten seconds, it's at 100% for those 2 seconds. When I would melt a big hunk of butter in my old microwave, I'd get really annoyed when I'd see the butter boil for five seconds, then just spin for five seconds, and so on.
Now with my new microwave, I can get really even melting or reheating, just at the expense of some time. I wouldn't consider buying a microwave without this feature.
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