Foo - Why does food get hotter......

....after you take it out of the microwave and let it sit a few minutes? Doesn't make any sense to me. :o

Thats right, it doesn't make sense. Unless you accidentaly set it down on top of a lit burner on your stove or something, it couldn't.

You been smokin any rocks or anything?

The microwave heats it unevenly, and in some cases heats the container. As it sits, the heat distributes, so some parts do get hotter.

the outside layer of the food gets the hottest, but as time passes that heat is transferred to the middle.

[e] cooker beat me to it.

You're probably not taking the food out of the microwave. You must be taking the food out of the fridge! Silly you!

Also called "carryover." Typically results from any cooking method. More severe with microwaved food, in my opinion, due to the speed at which it can be heated.

Makes sense cooker.

Thats why most directions say to mix or something after microwave...

I notice it most with frozen burritos. Even with it spinning around on the tray, there's usually one end that's hotter than the other. Let it sit for a while and the heat from the hot end moves over to the cool side. I also make sure I bite into the cooler end first, ended up with blisters on the roof of my mouth once. :(

This reminds me of that scene from "Mama's Boy"...

Burritos are bad at heating up. I usually just cut them up into smaller pieces and mix them around a bit. Doesn't look like a burrito any more, but it still tastes the same. My microwave at home is so old, and it only heats in certain spots inside.

Also called "carryover." Typically results from any cooking method. More severe with microwaved food, in my opinion, due to the speed at which it can be heated.

Yep +1

Also called "carryover." Typically results from any cooking method. More severe with microwaved food, in my opinion, due to the speed at which it can be heated.

Basically, it takes time for the heat that is absorbed (transferred) to the food to radiate away from the food. Before the heat can radiate away the object continues to heat up.

Huh?

The worst thing to heat up in the microwave is sugar. A jelly-filled Krispy Kreme doughnut that spends 5 seconds in the 'wave is so hot inside it will fry your mouth black. 5 minutes later it's still too hot to eat.

Danno' asked. . .

>>>Huh?

Gotta' agree with his confusion. I don't see here a cogent argument as to how an object can gain overall heat [as opposed to PERCEIVED locally sampled temperature] after it stops receiving energy.

Danno' asked. . .

>>>Huh?

Gotta' agree with his confusion. I don't see here a cogent argument as to how an object can gain overall heat [as opposed to PERCEIVED locally sampled temperature] after it stops receiving energy.

Microwaves cause water, fat, and sugar molecules to vibrate 2.5 million times per second, producing heat. After the oven is off or food is removed from the oven, the molecules continue to generate heat as they come to a standstill. This additional cooking after microwaving stops is called "carryover cooking time," "resting time," or "standing time."

Courtesy of : http://www.fsis.usda.gov/Fact_Sheets/Microwave_Ovens_and_Food_Safety/index.asp

A car's engine gets hotter after it is shut off. The ground gets warmer after the summer soltice. Very simple science.

OK, using simple momosyllabic words here so's I can understand it. . .while the food receives no additional energy input, the proportion of existing energy degrades from that involved in holding excited electrons in higher orbits into heat . That makes good sense; all energy degrades through the infra red as per the greenhouse effect.

[I]>>> The ground gets warmer after the summer soltice.

I don't completely buy that one, tho'. Seems to me the sun doesn't stop shining on the solstice so there's still radiation input. . .ALTHOUGH all wavelengths in eventually degrade through the IR, so your argument is valid to an important extent.

Anyway EDP', thanks for 'splaining this to us. Interesting phenom, eh?

Microwaves cause water, fat, and sugar molecules to vibrate 2.5 million times per second, producing heat. After the oven is off or food is removed from the oven, the molecules continue to generate heat as they come to a standstill. This additional cooking after microwaving stops is called "carryover cooking time," "resting time," or "standing time."

Courtesy of : http://www.fsis.usda.gov/Fact_Sheets/Microwave_Ovens_and_Food_Safety/index.asp

A car's engine gets hotter after it is shut off. The ground gets warmer after the summer soltice. Very simple science.I think we have to separate "small localized area" from "total heat". There may be hot spots on or in the food. And there will be colder spots. If you sample a cold spot and wait a while, yes, it will be hotter later. However, some other hot areas will have gotten cooler as well. The overall heat-content remains the same (some is lost to the atmosphere through radiation). Please review the 1st law of thermodynamics (http://en.wikipedia.org/wiki/Laws_of_thermodynamics)

Heat soak in an engine is the same scenario. During operation, the radiator pulls in cool air from the outside to help cool the coolant and blows some of this air across the engine. Also a moving car creates a lot of turbulence underneath and in the engine-compartment leading to cooling of the surface of the engine to around 120-150 degrees-F. HOWEVER, the inside the engine, the coolant is at 180-220 degrees-F and the combustion-chambers faces temperatures in the 1500-1800 degreeF range from burning gases. When you stop the car and shut OFF the engine and, the surface will no longer be cooled by moving air. The hot inner core of the combustion chamber heats up the coolant, which then heats up the outside surface of the engine. If you touch the engine a couple minutes after it's turned off, it'll feel hotter, but that's NOT because it's gained additional heat and energy. The cooler surface has just been heated up by hotter parts elsewhere. Same with food coming out of the microwave, some areas will get hotter through conduction of heat from hot spots, but overall heat content will be the same.

Another example is a glass of cold water with ice cubes. If you stick a thermometer and measure temp of water right after adding ice-cubes, you'll see it's 50-70C. After letting it sit for a while, the water-temp will be 5-10C. Did the heat in the water magically disappear? No it was transferred to the cold-spots in the drink, the ice-cubes. Total heat of the system remains the same. You can't create energy from out of thin-air or destroy it either, it has to come from and go somewhere.

The worst thing to heat up in the microwave is sugar. A jelly-filled Krispy Kreme doughnut that spends 5 seconds in the 'wave is so hot inside it will fry your mouth black. 5 minutes later it's still too hot to eat.

The worst thing to heat up in the microwave is the cat. :rolleyes:

You guys ever blow up toads in the micro?

>>> The ground gets warmer after the summer soltice.

I don't completely buy that one, tho'. Seems to me the sun doesn't stop shining on the solstice so there's still radiation input. . .ALTHOUGH all wavelengths in eventually degrade through the IR, so your argument is valid to an important extent.

Anyway EDP', thanks for 'splaining this to us. Interesting phenom, eh?

You are correct that the sun does not stop shining after the solstice, but that is the day with the longest input of heat from the sun, not factoring in clouds. Without getting into a lengtthy discussion, which I do not have the time to do, the heat absorbed deeper into the ground radiates back to the surface. I was just using this as an example.

As Danno pointed out, an engine, even an air cooled engine, has the heat from inside radiate back to the surface area, which raises the surface temp. How long does not matter, but the temp does rise on the outside surface.

You guys ever blow up toads in the micro?

yes

You are correct that the sun does not stop shining after the solstice, but that is the day with the longest input of heat from the sun, not factoring in clouds. Without getting into a lengtthy discussion, which I do not have the time to do, the heat absorbed deeper into the ground radiates back to the surface. I was just using this as an example. I think this case is where the ground is hotter than the air at night. However, the ground doesn't get hotter than its highest during the day. For example, during the day, the air-temp may reach 80F out and the ground may reach 90-F in the sun. Then after the sun sets and it gets dark, the air-temp will drop to 60F. However, the stored latent heat in the ground will then be radiated back up. The ground may then be 70F, it's hotter than the air, but it's NOT getting hotter and hotter.

yes

Really? Did you have to clean up?

>>> You guys ever blow up toads in the micro?

I'd like to ask humbly that we not do. In praise of toads, apart from their superb adaptability, stately position in evolution's panoply, dashing good looks. . .and a remarkable tongue, they are supreme bell-wethers of a degrading environment. We BFers tend to admire such things.

Well, there must be a degrading environment inside my microwave then! But no, I haven't nuked a toad before, that would be a mess to clean up. Has anyone here ever tried the grape plasma trick thingy? I might have to try it one of these days...

I think we have to separate "small localized area" from "total heat". There may be hot spots on or in the food. And there will be colder spots. If you sample a cold spot and wait a while, yes, it will be hotter later. However, some other hot areas will have gotten cooler as well. The overall heat-content remains the same (some is lost to the atmosphere through radiation)..............

I gotta think that's what's going on. I guess the food item doesn't get hotter overall(as I first stated), but the heat of the food item is more even overall. Makes sense to me.

Don't have any experience cooking toads.

It's like a block with a bunch of parties going on. All the bumping and grinding is happening in just a few apartments or bars - the rest of the block is dead. But sooner or later, the partiers pour out into the street and bump into all the bums. Before you know it, EVERYONE is rocking out.