If you have a fixed quantity of frozen peas and you want to cook them as quickly as possible in the microwave, should you boil the kettle and then (a) add just enough boiled water to cover the peas comfortably or (b) add more water than that. In both cases you will bring the water back to the boil in the microwave, at which point you will regard the peas as cooked.
It is assumed that the kettle has been boiled in anticipation, so only the time in the microwave is at issue.
Bill
It doesn't make any difference. The time is determined by the amount of heat required to raise the peas from T=0 to T=100, and this fixed amount of heat = time x (microwave power). This assumes that the full power of the microwave is absorbed by what's inside it.
We can probably assume that the amount of heat energy absorbed by food in a microwave is approximately proportional to the time spent in it.
We can assume further that the amount of energy to boil the peas themselves is fixed. I have no idea what amount of peas you mean, nor of their specific heat, though I can guess that, since living things mostly consist of water, it won't be much different from that of water. But anyway, to raise a given amount of peas to boiling requires a given input into the system which is unaffected by how much water you add. Let's call this amount of energy P.
However the water added will lose heat energy during the transfer, and not all of that heat will go into the peas, it being necessary to replace any amount lost by energy from the microwave. Further, the more water you add, the more heat will go astray, and have to be replaced.
Let us consider two quantities of water as examples.
Suppose that first we add just enough water to cover the peas. Some of its heat will be transferred to the peas, but some will be lost to the environment. Let's call the amount of energy introduced by this amount of water W, and the amount lost dW. Thus the microwave has to supply P - W + dW to bring the peas to the boil.
Let's now try doubling the amount of water. The amount of heat required from the microwave is now P -2W + 2dW.
Well, actually, it's more, because heat is being lost to the environment all the time, even while the microwave is cooking the food, and because the greater amount of water will take longer to heat, more heat will lost to the environment during the process, and have to be replaced by even longer cooking.
So a lot depends on whether dW is greater than W. It is relevant here is that the amount of heat lost is dependent largely on the heat gradient - that is the hotter the water is relative to its surroundings, the greater the heat gradient between itself and its surroundings, so the more rapidly it is losing energy to those surroundings. The water will be losing heat most rapidly at the moment of power disconnection.
However, a full analysis would require actual numbers which you haven't supplied and which, OOTTOMH, would be difficult to guess with sufficient accuracy. Without hard numbers, it's not possible to say either way.
Of course, if you're c> If you have a fixed quantity of frozen peas and you want to cook them as
Easy, before placing in the microwave, use petrol instead of water.
Steve Terry
However, if you can seal them in, water boils at a higher temp than in normal atmosphere. Does this all really matter, I'm a great one for testing things. Its amazing how often I find stuff that is mega hot in one place but not in another, even if the majority of the thing is water.
Brian
Could one ask for what reason this really matters in the vast scheme of things? Incidentally, there is a place darn sarf, that is called Peas Pottage. I don't know if the folk there are more knowledgable about peas though.
Brian
The time is also determined by the mass and specific heat of what's inside.
However, if you can seal them in, water boils at a higher temp than in normal atmosphere. Does this all really matter, I'm a great one for testing things. Its amazing how often I find stuff that is mega hot in one place but not in another, even if the majority of the thing is water.
+++++++++++++ Yes and no! The pressure will not rise UNTIL the water starts to boil so you will create pressure but only once the water has started boiling anyway. From then on any subsequent water that boils will boil at a slightly higher temperature thus pressure cookers [1].But as you say, for frozen peas, who cares? I suspect that using the "no water" method explained by another poster, the peas will be done almost before you've got the kettle filled.
Paul DS.
[1] And why you can't get a decent cup of tea whilst skiing in the Alps for the opposite reason.
Doing this by covering the peas means that cooking will be by diffusion of thermal energy into the peas, as the water will screen them from the microwave energy. Therefore, they will cook in the sake time using any other form of heat to boil the water.
Putting the peas directly in the microwave cooks them with the microwave energy that can penetrate the peas. This is likely to be an order of magnitude faster than the diffusion method.
You don't add any water, you just put the frozen peas in a jug and nuke them. That is the quickest, cheapest and produce the best taste. A rare case of win, win, win.
Petrol boils at a lower temp than water, so the cooking will take longer. Also a microwave is tuned to a frequency so that water absorbs the energy. I expect that's a different frequency for petrol.
neither. Put them in the microwave with no water at all, a little butter and for best results use a bit of plastic film to cover them
Have often thought it would be interesting to have a tunable microwave. That frequency is just right for oil so will make a nice hot surface on a chip. This is spot on for alcohol so will be ideal for warming brandy to flame the Christmas pudding.
And, of course, we'd need the frequencies for tar, Araldite, etc...
Its quicker to add no water, then teh peas are cooking entirely by microwaving rather than partly by boiling water.
NT
The 2kw kettle will boil water quicker and because all of the power goes into the water more efficiently. An 850watt microwave will at best be 50% efficient even if all of the radiation is absorbed by the peas + water.
But that's because you spill the tea due to bumpy snow.
Those two things determine the amount of heat required. The point is that it is not affected by the amount of boiling water added. If the microwave puts only 50% of its power into heating, then the time is doubled - it is still independent of the amount of boiling water.
While the peas obviously do have water in them, it may not be enough to 'load' the microwave oven sufficiently (obviously depending on how many peas you have). A little additional water may be necessary, if only to keep the oven happy - and if you're going to have it, you might as well use it to help cook the peas.
Many kettles have a minimum water level which would imply heating far more water than needed for a few peas. Therefore, time to boil will very likely be more than you seem to imply from taking power figures.
Further, as already said, you need to heat the peas PLUS added water to boiling. Whereas direct in microwave without added water means less water being heated.
With what I consider a single portion (maybe equivalent to a tea-cup?) never had a problem.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.