My green beans are afire.

[jonhaggis]

I am neither quack nor scientist. I am actually an English teacher in the suburbs of Chicago. But I do know what I know, especially from empirical evidence, and I can say that this is true: when my wife or I microwave green beans they spark. Lots of sparks. Given time, they blacken and smoke. My question is: why?

The beans themselves are often on a paper plate. But we've also seen it in a plastic bowl. No, I am not a complete idiot, and they are not in a metal bowl or a glass bowl with a metal rim. It has happened with bagged, washed beans that were steamed in the bag, but then spark when reheated.

I have seen a few theories on the web, including a longer one that delved into the shape of grapes, escaping steam, and the potential for arcing, sparks and flames. Some say dense vegtables like greenbeans and carrots have lots of minerals, thus the sparking. Well, I've never seen a carrot or other vegetable spark. But green beans? They spark. And no other satisfactory answer so far.

Ideas?

p.s.: this has not been a one time thing. The result is repeatable. Our microwave, by the way, is GE Spacemaker XL1800

[FoieGrasIsEvil]

I'm somewhat of a foodie, and without Googling, I am not sure what the deal is. I highly doubt that density and high mineral content would explain the sparking.
How new is your microwave? Any other problems with cooking any other foods in it?

One solution that is completely unrelated as to the why of your query is to quit microwaving green beans altogether.
Buy 'em fresh, wash and clean them, boil and blanch them, then transfer to a skillet with some butter and/or bits of bacon fat, a little shallot or onion, salt and pepper to taste and they're much better than microwaving.

Of course this takes more time, but it's sooo worth it by comparison...no sacrificing the crunchy texture of the bean, the color or the flavor.
Oh, and no sparking.

[FoieGrasIsEvil]

I read what presumably you read on "Yahoo Answers" after Googling "Sparking Green Beans".
I have no idea why it would do that. I've never seen it before and I have microwaved beans before, but only the prepackaged kind, never fresh ones.

[Joey P]

I have no idea why, but grapes will do this to. Take a grape, cut it in half, put the two peices, flat side down in the microwave, touching. Then turn it on and they'll arc. It doesn't always work though.

[ForumBot]

Originally Posted by FoieGrasIsEvil

Of course this takes more time, but it's sooo worth it by comparison...no sacrificing the crunchy texture of the bean, the color or the flavor.
Oh, and no sparking.

As much of a foodie as I am, canned green beans are an entirely different animal and can't be judged against fresh ones. There's just something satisfying about that soft green texture soaked in bean juice. Mmmmm.

[rowrrbazzle]

Here's info about the grapes from a microwave physicist at Hughes Research.

http://www.madsci.org/posts/archives...9591.Ph.r.html

[blondebear]

I noticed the sparking bean phenomenon a couple of years ago, specifically with the ones I got from Trader Joe's. I thought about starting a thread to seek enlightenment, but never got around to it. So, thanks for bringing the question up.

[FoieGrasIsEvil]

Originally Posted by ForumBot

As much of a foodie as I am, canned green beans are an entirely different animal and can't be judged against fresh ones. There's just something satisfying about that soft green texture soaked in bean juice. Mmmmm.

Oh, I like canned green beens too. I believe the OP was referring to bagged nukeable ones, which IMO are the worst of all kinds.
But I always do canned beans in a pot on the stove, with the juice of course.

[lobotomyboy63]

Any spices in the beans? I notice my potato casserole will do that when reheating and I think it may be all the pepper I put in it.

[FoieGrasIsEvil]

Originally Posted by lobotomyboy63

Any spices in the beans? I notice my potato casserole will do that when reheating and I think it may be all the pepper I put in it.

Really? Pepper? I don't know about that. I am a pepper-snorter, and it doesn't arc inside my nostrils.

[lobotomyboy63]

Originally Posted by FoieGrasIsEvil

Really? Pepper? I don't know about that. I am a pepper-snorter, and it doesn't arc inside my nostrils.

I nuked some pepper in the microwave after posting. No deals. Next hypothesis....

[FoieGrasIsEvil]

Originally Posted by lobotomyboy63

I nuked some pepper in the microwave after posting. No deals. Next hypothesis....

Ha! Although there is truth in the fact that if you try to microwave something without *any* moisture in it, it will catch fire. Try nuking straight cocoa powder sometime.
My brief understanding of microwaves is that they excite molecules in the food that contain moisture, thereby exciting them into movement, which generates "heating from within". My limited understanding also says this is why you often have to stir microwaveable foods halfway through cooking to evenly distribute the heat instead of allowing the edges of it to fry.

My astronomy professor also said that the reason microwaves had that "screen" on the door that has all those small holes in it was to reflect microwave radiation back into the microwave, with the reasoning being that microwaves are a really long wavelength of light, and thusly are repelled by the holes in the screen that they cannot pass through, only to bounce around inside the microwave and cook the food radiactively some more.

Somebody correct me if I'm wrong.

[Nametag]

Originally Posted by FoieGrasIsEvil

Ha! Although there is truth in the fact that if you try to microwave something without *any* moisture in it, it will catch fire. Try nuking straight cocoa powder sometime.
My brief understanding of microwaves is that they excite molecules in the food that contain moisture, thereby exciting them into movement, which generates "heating from within". My limited understanding also says this is why you often have to stir microwaveable foods halfway through cooking to evenly distribute the heat instead of allowing the edges of it to fry.

My astronomy professor also said that the reason microwaves had that "screen" on the door that has all those small holes in it was to reflect microwave radiation back into the microwave, with the reasoning being that microwaves are a really long wavelength of light, and thusly are repelled by the holes in the screen that they cannot pass through, only to bounce around inside the microwave and cook the food radiactively some more.

Somebody correct me if I'm wrong.

Well, that's why there's a shield in the door, yes; not only for efficient cooking, but for safety. The holes are just there so you can see through it, though; the relatively long wavelength allows the holes, but it doesn't require them. The uneven cooking is due to uneven distribution of energy inside the oven and incomplete penetration into the food. Carousels solve the first, but only stirring (or waiting for heat to diffuse) can solve the second.

As for why green beans are more likely to spark than other vegetables, maybe it's the shape? You know, pointy?

[Cervaise]

Originally Posted by rowrrbazzle

http://www.madsci.org/posts/archives...9591.Ph.r.html

I found that single grapes would eject steam out of the stem hole forming little rocket engines which often propelled the grapes about the oven.

[teela brown]

I like to "saute" a bit of chopped garlic in the micro. I put it in a small Pyrex bowl with a dribble of oil, and give it 30 seconds or so. It will often "spark", and it's the only thing I've noticed that does this. My bacon doesn't do so, nor do my leftover reheats.

[Anne Neville]

I've microwaved canned and frozen green beans, and never noticed anything like this. I do always sprinkle a little water over any vegetable I plan to microwave, though.

Originally Posted by FoieGrasIsEvil

My astronomy professor also said that the reason microwaves had that "screen" on the door that has all those small holes in it was to reflect microwave radiation back into the microwave, with the reasoning being that microwaves are a really long wavelength of light, and thusly are repelled by the holes in the screen that they cannot pass through, only to bounce around inside the microwave and cook the food radiactively some more.

Light waves can't really see imperfections that are smaller than some fraction (which I forget, and my Google-fu fails me) of a wavelength. Those holes are smaller than that for the microwaves in your microwave, so they see the screen as one unbroken mirror. Visible light has a much shorter wavelength, so it has no problem getting through those holes.

Incidentally, this is why radio telescopes can be made so much bigger than optical telescopes- radio waves have a longer wavelength, so the radio reflector doesn't have to be nearly as smooth as an optical reflector. We've got a 100-meter radio telescope, while the largest optical telescope in the world is only 10.4 meters.

[Frylock]

On my local news the other day they said "Scientists" told them it's because of minerals in the soil the veggies are grown in.

But that was local news. "Quoting" "scientists." So grain of salt.

-FrL-