Microwave ovens

[tipsy]

i loved watching those ads while i was all f#ckerd up...:p

[Mahk]

Lmao, jj!

This is your brain on drugs:
http://linkinn.com/image/art_egg.jpg

[harpy]

I don't normally take drugs, but after watching that video I have a sudden urge to. :confused:

[BlackCats]

:eek::D

[Fungus]

Just came across this thread .. seems to be a lot of misinformation about microwave ovens ..
They simply use a radio transmitter at very high frequencies which is tuned to the water molecules resonant frequency. It is not ionising radiation and there isnt any after .. And the metal cage of the microwave stops any radiation from coming out, in the door of the microwave there is small perforations which are smaller than the wavelength of the microwaves so you can look through but still not get any radiation. But even if you did, it only produces a heating effect ..
I can only really think of a few hazards of using microwaves:
If you heat up liquid in a microwave in a smooth container, there is a small chance of it exploding when you take it out/add powder to it; for water to boil it has to have 'seed bubbles' which form around tiny pockets of air and in a microwave with smooth containers the water can get superheated and above the boiling temperature of water, leading to a steam explosion when taken out. However this is easy to get around by adding whatever powder (sugar etc) first before it's put into the microwave.
Then if you have metal objects in a microwave oven they can heat up a lot and be dangerous; they act as antennae for the microwave frequency and an electrical current builds up inside them, because of the resistance of the metal this produces a lot of heat as the eddy currents flow round them.
The reason why a lot of food seems not 'properly cooked' is really because of the inherent properties of the microwave that means it cooks food thoroughly all the way through, meaning it doesnt get 'crispy' on the outside, a lot of new microwave ovens also have a normal element for this purpose ..
And since microwaved food isnt cooked inside anything else which can leach away the nutrients the most that can happen is denaturing of some proteins and enzymes at very high temperatures which happens with any food that is heated up.

[Mahk]

Bravo Fungus! I'm glad to see another forum member apply science instead of superstition to the topic at hand.

From my understanding microwave ovens cook based on friction which generates heat. Much like when one rubs their hands together to warm them on a cold day. Each water, oil, and other polarized molecules in the food vibrates against each other due to the oscillating microwave field and the friction then generates heat.

Water has a hard time reaching temperatures much above boiling (100C/212F), it simply vaporizes in to steam, but oils and tomato based foods have the potential to reach much higher temperatures so they should not be cooked in plastic containers which may melt or leech bad chemicals into the food. Use glass instead.

Very early designs made in the 1950's didn't always have an interlock which prevents operation while the door is open. Those potentially could cause some health issues if the owner opened the door while the unit was on, but otherwise modern day microwave ovens are quite safe.

[Mr Flibble]

Bravo Fungus! I'm glad to see another forum member apply science instead of superstition to the topic at hand.

From my understanding microwave ovens cook based on friction which generates heat.

Exactly, it's science innit? The plate in the microwave goes round, generating friction, which causes heat. The whole micro waves thing is just to throw the hippies off :p

[Fungus]

:)



The plate only turns to prevent 'hot spots' created by standing waves making bits of the food hotter than other though :)

[citameht]

I use the microwave oven almost exclusively for cereals.

[Zero]

Microwave ovens are no more destructive than any other form of heating, the high frequency waves cause water molecules to rub against each other creating molecular friction and thus heat.

The energy is changed to heat as soon as food absorbs it, therefore it cannot become radioactive or contaminated.

Microwaves are reflected by the surfaces inside the oven so as long as your microwave oven is in a good state of repair and you are using it correctly the radiation does not escape beyond safe "leakage" levels.

Microwaves have a frequency of 2,450 MHz. The microwaves then pass into the enclosed metal oven cavity where they are reflected around the oven walls and absorbed in food or drink placed in the oven.

If you are truly worried about the effect magnetic fields will have on your health then you should also stop using cellular/mobile telephones, cordless phones and wireless networking technology as they all emit similar magnetic fields and do so for longer sustained periods of time.

If you are convinced that microwave heating contaminates your food somehow then you should perhaps switch a raw diet because it essentially heats organic matter in the same way as any other conventional form of heating does.

Useful reading:
http://www.ccohs.ca/oshanswers/phys_agents/microwave_ovens.html (http://www.ccohs.ca/oshanswers/phys_agents/microwave_ovens.html)
http://www.doh.wa.gov/ehp/rp/xray/rp-oven.htm (http://www.doh.wa.gov/ehp/rp/xray/rp-oven.htm)
http://www.howstuffworks.com/microwave.htm (http://www.howstuffworks.com/microwave.htm)

I don't own a microwave presently. Not because I am afraid of them, but because I find they make me lazy and I end up cooking things late at night when I otherwise wouldn't bother by any other method, I am sure I will end up getting one again at some point though.

I think they do have the potential to destroy more nutrients than other forms of heating simply because they heat things faster and have greater potential of "over heating" foods.

In my opinion consuming fizzy drinks and processed sugar is more damaging to human health than microwave oven emissions :)

[Zero]

Water has a hard time reaching temperatures much above boiling (100C/212F), it simply vaporizes in to steam, but oils and tomato based foods have the potential to reach much higher temperatures so they should not be cooked in plastic containers which may melt or leech bad chemicals into the food. Use glass instead.


This is a valid point, you should always ensure you use "microwave safe" containers when heating food, nothing that will begin to melt or break down as a result of the food or drink heating up.

[harpy]

ISTR that the best-substantiated objection to microwave cooking (at least for vegetables) is that you usually have to cover them in water, so nutrients leach out into the water during cooking (as with boiling). So steaming or stir-frying would probably be a better way to go for most things.

I expect I already said this earlier in the thread :o

[Risker]

I don't think that's right harpy, in fact I think it's the complete opposite. You can cook most vegetables in the microwave with little or no water, meaning they retain more nutrients than other methods of cooking.

[Zero]

I certainly never added any water to frozen veg when I microwaved them. I don't see the point, it just takes longer.

[cedarblue]

interesting thread, and like korn i am 0% knowledgeable on microwaves.

i still dont have one and dont want to use one, it just doesn't feel right for me. i would rather steam veg and bake potatoes etc. why the rush in preparing/cooking food? cooking is half the enjoyment for me when i cook stuff. i have no proof that ovens are any safer than micros but thats just what i do.

[Mahk]

Some vegetables I cook directly in the microwave but some are prone to drying out. The excitation of the water molecules turns them to steam and they leave the vegetable and enter the air. I have frozen pot stickers (Chinese dumplings) for example that will become dry and crusty if I cook them too long. I find for them, as well as other things that dry out, the best approach is to wet their outer surface, put them in a very small puddle of water (1-2 TBLS) cover the bowl with saran wrap ("cling wrap" I think those of you on the other side of the pond call it, no?). If you do so tightly the steam will cause the plastic to dome at first and then suck down and cover the food tightly once the cooking stops. If this is undesirable a small slit about 1 centimeter long in the top will act as a pressure escape valve yet still allow a good degree of "steam cooking" action to occur.


When nutrients are "lost" from cooking it is really that they have been relocated to the steam or boiling water. Ever notice the water is no longer clear at the end of the cooking process? It has become nutrified (if there is such a word). If one consumes that water, say for example when cooking vegetables for a soup, one has gained back the escaped vitamins/minerals. They are arguably even better as they will be more bio-available since your stomach acid is no longer needed to leech them away from the solid food.

[Ruby Rose]

why the rush in preparing/cooking food? cooking is half the enjoyment for me when i cook stuff.

I like cooking too, but seldom have the time to cook a full meal from scratch after I get home from work in the evenings. It's not so much that I want food in a hurry - it's more that I want food before midnight! We tend to use the microwave to reheat pasta etc, and to cook frozen veg.

[Gorilla]

i still dont have one and dont want to use one, it just doesn't feel right for me. i would rather steam veg and bake potatoes etc.

the only things i really use microwaves for is to cook jacket potatoes, because i prefer the way they turn out, i don't like the skins going all hard and dry in the oven - and to reheat leftovers.


cover the bowl with saran wrap ("cling wrap" I think those of you on the other side of the pond call it, no?).

cling film we call it. i had no idea you guys call it saran wrap. what does that mean?

[Zero]

When nutrients are "lost" from cooking it is really that they have been relocated to the steam or boiling water. Ever notice the water is no longer clear at the end of the cooking process? It has become nutrified (if there is such a word). If one consumes that water, say for example when cooking vegetables for a soup, one has gained back the escaped vitamins/minerals. they are arguably even better as they will be more bio-available since your stomach acid is no longer needed to leech them away from the solid food.

It is the heat that destroys the nutrients and enzymes, I can imagine that the water is more "nutritional" than it was prior to the cooking process but certainly not containing anywhere near as many nutrients as the food.

[harpy]

This I think is the source of the point about water in the microwave:

http://news.bbc.co.uk/1/hi/health/3188558.stm

(ETA as you see it's not that recent.)

I'll need to take people's word for it as to whether you do or don't need water for microwaving as I never cook anything in the microwave. I have been known to use it for last-minute defrosting though.

[Mahk]

Gorilla, Saran brand was probably the first to market so their name became synonymous with the product (here at least), similar to Vaseline brand petroleum jelly [not vegan, filtered through bone char BTW] or Kleenex brand tissues [sorry, I don't know what you call that in "English":), perhaps the same] or old people may refer to microwave ovens as "RadarRanges". (http://www.smecc.org/microwave_oven.htm)

[Mahk]

This I think is the source of the point about water in the microwave:

http://news.bbc.co.uk/1/hi/health/3188558.stm
It is important to note that the 5 oz. of broccoli that lost much of its vitamins was sitting in 2/3 cup of boiling water (http://www.webmd.com/food-recipes/news/20031029/hot-water-kills-broccoli)! The microwave oven had nothing to do with any nutritional loss in that study, it was the boiling water the broccoli was immersed in. Boiling is boiling.

[Mahk]

It is the heat that destroys the nutrients and enzymes, I can imagine that the water is more "nutritional" than it was prior to the cooking process but certainly not containing anywhere near as many nutrients as the food.
Zero, I don't know if it is the "law" that a vegan has to believe in the benefits of the raw food movement (it seems so reading various threads here in our forum) but I for one don't. I've looked for and have never found a scientific experiment, published in a peer reviewed scholarly journal, which supports it, just anecdotal "I feel so much better" tales. Everything I mentioned regarding the fact that vitamins don't disintegrate into thin air and get destroyed but rather are relocated to the water is documented here (http://www.drfuhrman.com/faq/question.aspx?sid=16&qindex=4) as well as the truth about the "enzymes". Further discussion would probably be best for another thread that I'm reluctant to start since enough people already hate me because I dare to discuss topics such as if animal testing exists for any reason. [ I don't condone it in any way, of course.]

[harpy]

It is important to note that the 5 oz. of broccoli that lost much of its vitamins was sitting in 2/3 cup of boiling water (http://www.webmd.com/food-recipes/news/20031029/hot-water-kills-broccoli)! The microwave oven had nothing to do with any nutritional loss in that study, it was the boiling water the broccoli was immersed in. Boiling is boiling.


Yes, that point is made in the BBC report as well.

[Mahk]

If one reads the whole report, true, but a cursory look at just the title implies otherwise:
"Microwaved veg 'loses nutrients'

Vegetables cooked in the microwave may lose ingredients that could help fight cancer."

Using a microwave to boil vegetables seems odd to me. The "steaming" method I described or alternatively no water at all process should be much quicker for one thing. Isn't the whole point of a microwave oven speed? If one submerges broccoli in water the broccoli itself is hardly cooking until the water actually comes to a boil. The water effectively is shielding the broccoli from the direct microwaves themselves and a 2/3 cup of water probably takes about a minute before it will boil (depends on wattage, container etc)