Not really. Boiling point is in any case arbitrary. It varies with the concentration of material dissolved in the water, and with air pressure. The real point is that the food must be kept at a given temperature for a given time. Roughly speaking, for every ten degrees cooler (around cooking temperatures) every ten degrees cooler means double the cooking time. That can mean a considerable penalty in energy unless your casserole, or oven depending on the setup, is very well insulated.

Pete, what you say is, if anything, even more obviously sensible. However there are a few complications (aren't there always? I sometimes think that science was invented to confuse us; where did you ever see a worthwhile scientific answer that did not raise more questions?)

Okay, first off, there is the question of speed. The higher the temperature gradient between the oven and the (watery) food, the faster the heat gets in. Such convection as there may be will be more vigorous and even the rate of convection will be higher (somewhat anyway, don't ask me how important that would be!) Anyway, for a given oven setting, up to a point, one would expect the temperature to determine the duration of cooking. Irish stew? Hmmm... It is rather watery stuff, not like our South African bredies, which one certainly must not overheat too abruptly, unless you want a pot full of nasty burnt taste.

Also, next time you spill some of your Irish stew on a hot plate note what happens to it between the time of heating up and drying out. It goes through quite a range of temperatures as it loses water and as various components begin to decompose and give up chemical heat.

Placing something in a hot oven is inclined to cause local heating with similar results where viscous regions can become a great deal hotter than the boiling broth.You will notice that a major theme of this discussion has nothing to do with equilibrium states, but transient states between raw, cooked (but insipid), and cooked with complex and authoritative tones of crust and scorch, much like the crust on bread.I am wandering. Let's leave it there for now. Was that the kind of answer you wanted?

Cheers,

Jon

Unlike a digital still camera or a digital movie camera, the human eye does not have a shutter and does not build up a picture in frames. What the brain gets is a continuous stream of information from each each individual cone or rod. The total data rate along the optic nerve from eye to brain is thought to be about 10Mbits per second. The density of the light receptors is not uniform across the field of view but has a high density in one area for gathering concentrated information and one area, where the optic nerve connects, that has no receptors. When looking at a scene, the human eye moves around looking at different areas and the brain puts the whole thing together. The brain will also fill in missing bits to make sense of the whole scene, not the sort of thing that a camera does.

Now, if we look at our ability to resolve images on a printed card, we find that a camera would require about 74Mpixels to achieve the same. If we now look at the human eye observing an everyday scene, with the eye moving around to take in the whole scene, we come to a requirement of around 576Mpixels.

The ISO number for a dark adapted human eye is around 800. Now full dark adaption takes about 30 minutes to take place. Once adapted you will find that the eye is integrating information over about 10 to 15 seconds. At low light levels the eye does not attempt to use colour, just black and white. The total range of brightnes tha the eye can see over is about 10^7 to 1 and the contrast ratio is about 10^4 depending upon total brightness.

The colour depth is difficult to work out but is given as equivalent to 8 bit at best but most likely 5 bit.

The focal length is about 25mm with an apature of 7mm making the eye f3.5.

The eye does not zoom but it does have one small area that has a higher density of receptors than the rest which can resolve better detail.

The eye does not have a shutter and does not construct frames but the response time of the receptors is such that it coresponds to a frame rate of about 15fps. This will give you an idea of blurring. Remember that the brain is able to process out a great deal of blurring.

The brain does compensate for white balance.

Answering with my chef’s hat on, rather than a scientist, I find that the higher temperature causes meat (and veggies) touching the outer edge of the pot to get heated well above boiling, and introduce both textures and flavors you would not get with a lower temperature

I have been giving this some thought, mostly about different sorts of ovens. I love ovens.

First of all, in a conventional oven, heating a casserole is partly by conduction from the air and partly by radiation from the walls of the oven. A boundary layer of coolish air forms around the casserole insulating it from the rest of the air in the oven. A more modern fan oven circulates air around which strips off the insulating layer and enables the use of lower temparatures. Inside the casserole a thin layer of liquid also insulates the rest of the contens from the wall of the casserole. A highish temperature is requied to overcome the insulating layers and cook the food in a reasonable amount of time.

Also remember that the temperature of the oven is not uniform. The fairly crude thermostats used in most ovens, at least the ones that I can afford, do not exactly maaintain an even temperature.

It is nice to imagine that boiling water has a temperature of 100c, it does not. There can be, I think, about 8c difference between one bubble an hour and a raging blast the contents of the casserole all over the oven boil. A more robust boiling will cook the food quicker.

As a matter of interest, the ovens with conveyor belts in them that are use to cook pizza blast hot air onto the food from above and below. This is why your pizza gets cooked so quickly but does not blend the flavours as well as you can do at home.