In article >,
Sheryl Rosen > wrote:
> in article , at
> wrote on 12/29/03 9:18 PM:
>
> > So can you explain why? Or not?
>
> It works.
> It's something to do with physics.
>
> All I need to know is, when I follow the rule, my food doesn't stick and I
> don't get greasy globs that don't scrub off on my pans. And when I put the
> oil into a cold pan, then add the food....my food sticks to the pan and I
> have a mess.
>
> So i don't ask questions, I just accept it as nature and follow it and I
> don't have any trouble.
As a recovering physicist, I always ask questions. Here we go again -
I'm having a relapse. :-)
Consider three frying methods:
(a) Put oil and food in pan, then heat.
(b) Heat the pan, then add oil and food at same time.
(c) Put oil in cold pan, heat the oil, then add food.
(d) Heat the pan, add oil to hot pan, heat oil, then add food.
Has anyone here actually done a careful comparison to see if Sheryl's
recommended method (d) results in less food sticking than the others?
Maybe I'll try this out and report the results here.
Over the years, I've probably done all 4 of these methods. Can't say
that I've noticed any substantial difference in food sticking. If I had
to guess, before doing the test, I would venture that (c) and (d) might
produce less sticking than (a) and (b). If the food hits hot oil, and
the browning reaction starts immediately, perhaps this changes the
external surface of the food before it can adhere to the pan. But it's
not obvious to me why there should be less sticking with (d) than (c),
as Sheryl claims. Does the oil react differently to slow vs. sudden
heating?
Or does the pan react differently if we preheat it before adding oil?
Some people claim that preheating closes the "pores" on the pan's
cooking surface. See for example
<http://ths.gardenweb.com/forums/load/cookware/msg0623090428443.html>
But my recollection from physics is that thermal expansion causes a
solid body to expand proportionally in all dimensions. The pores should
get larger. Perhaps the preheating drives moisture (or other
contaminants) off the cooking surface.
--
Julian Vrieslander