On Wed, 16 Aug 2006 06:03:09 GMT
Mike H > wrote:
> wrote in news:1155583971.668535.290230@
> 74g2000cwt.googlegroups.com:
>
> > You're opening a can of worms with that question. One particular
> > pompous blowhard on here refused to admit I was right. I ended up
> > having to killfile him. I saw his picture one time and he even
> > looks like a fat pompous blowhard.
> >
>
> Actually, while your observations were on target, that an aluminum pan
> doesn't brown like other materials, your terminology was wrong. The
> reason they don't brown as much is not because of reflecting heat,
> but rather poor conduction of heat due to lack of mass.
The truth is far more complex than mass or conduction or
reflectivity.
If this were about mass, lead would be a great cooking material.
Setting aside heavy metal toxicity, I'll give you a hint - it isn't.
Quite poor, in fact.
Reflectivity does play a part in the oven - things that are black
absorb a broader spectrum of the radiant energy in an oven than things
that are not black. This has not been in dispute since the days of the
Count von Rumford.
The cornerstone of this argument, the piece you completely overlook,
is specific heat, and how it relates to the density of a material. Mass
is just one part of the density question.
I'm not about to go into tremendous detail. I already did that over
in rec.food.drink.tea several months back when someone was aghast that i
never bother to preheat featherweight glass teapots that have a paltry
440 joules per kilogram-kelvin to offer me. Granted, the argument at the
time was about stored energy.
Here's the basics: Ignoring for the moment the difference in density,
iron and steel have about half the specific heat of aluminum, which is
expressed as a measurement of joules of energy per kilogram.
What this means, in the most basic of terms, is that given the same
mass and the same surface area, and similar surface features, a steel
pan will buffer about half the amount of energy that aluminum will
before conducting it to the food.
It all conducts at something real close to the speed of light, so
"faster" isn't the right term. There's just more conduction going on in
the steel.
No material is "better" in all cases. I make bread in steel pans
because i like the browning qualities and the resulting crust formation.
I make cake in aluminum pans because i like the browning qualities and
the resulting crust formation.
I have one aluminum bread pan. I tried making bread in it once. I
prefer to make pound cake in it.
I have intentionally left out references to the mean thermal
conductivity of these materials. I don't feel like looking that up
today. If you want to have fun with that, Pyrex is about 450 k/kg-k too.
Figure out why it doesn't behave exactly like steel.
Arguments of shiny vs. dull should take into account issues like
surface area on a molecular level, and the fact that aluminum oxide is a
better thermal conductor than aluminum. Black vs. metal-colored was
settled over 200 years ago.