> Color is a biochemical process. Pink is meat without the proteins
> denatured. Once there is no more pink, all of the protein are
> denatured and the heat energy must find the chemical reaction
> with the next highest activation energy.

Ok... but a steak isn't a fluid; heat isn't evenly distributed. While
you're still busy denaturing proteins in the middle, you must be also
binding connective fibers and making the meat tough on the outside, all at
the same time (at least with a steak of any reasonable thickness). (Not
being a food chemist, I'll take you word for it that that's what happens.)

> In specific the binding of
> connective fibers to make the meat tough. There is an amazing
> lack of overlap of the two reactions.

Why is that? This is what I don't get. It's not like losing the last of
the local pink suddenly makes that meat a much more efficient conductor,
passing the rest of the heat along to the middle where it's still needed. :-)

Of course, this is only really of academic interest for me; I like a steak
rare to medium-rare anyway (and not just because it gets tough when
overcooked; it tastes better when more rare also, for me).

> Chemistry. Heat of activation. Heat tends to flow to the reaction
> that has the lowest heat of activation.

Heat tends to flow (in a solid) according to how good a conductor of heat
that solid is. It doesn't depend on whether a low-activation reation is
waiting to the left rather than to the right. :-)


-C

Chris De Young wrote:
> Doug Freyburger wrote:
>
> > Color is a biochemical process. Pink is meat without the proteins
> > denatured. Once there is no more pink, all of the protein are
> > denatured and the heat energy must find the chemical reaction
> > with the next highest activation energy.
>
> Ok... but a steak isn't a fluid; heat isn't evenly distributed. While
> you're still busy denaturing proteins in the middle, you must be also
> binding connective fibers and making the meat tough on the outside,
all at
> the same time

Correct. That's why thinly sliced beef like in a Philly Cheese Steak
is
easy to get tender and well done, why a steak the thickness of my
hand can only be pulled off by one cook in a hundred, and why a
roast is out of the question unless you're willing to cook that roast
past the point of tough until it falls off the bone.

> (at least with a steak of any reasonable thickness). (Not
> being a food chemist, I'll take you word for it that that's what
happens.)

The thicker the steak the harder to pull it off. Get a steak as
thick as a filet minion and forget it. Not enough time for the
heat to flow into the middle.

> > There is an amazing lack of overlap of the two reactions.
>
> Why is that? This is what I don't get. It's not like losing the last
of
> the local pink suddenly makes that meat a much more efficient
> conductor, passing the rest of the heat along to the middle where
> it's still needed. :-)

A steak while cooking will conduct enough that a perfectly tender
well done steak is possible so long as you use a steak no thicker
than my hand and you have a cook capable of knowing which
one second period it will start getting tough.

> Of course, this is only really of academic interest for me; I like
> a steak rare to medium-rare anyway (and not just because it
> gets tough when overcooked; it tastes better when more rare
> also, for me).

I like the flavor of a well done steak better when I think it is
possible. As a result I order my steaks medium in any
restaurant I've been to under a dozen times until I know who
the cook on duty is. I am well aware that it is impossible to
the vast majority of cooks including myself.

> > Chemistry. Heat of activation. Heat tends to flow to the reaction
> > that has the lowest heat of activation.
>
> Heat tends to flow (in a solid) according to how good a conductor
> of heat that solid is. It doesn't depend on whether a low-activation
> reation is waiting to the left rather than to the right. :-)

Heat tends to flow from the source of heat to the point of lowest
temperature. To the extent allowed by conductivity it does not
flow in every direction. Any cooking process that is exothermic
will consume heat and tend to draw heat to the point of reaction
to the extent allowed by conduction. This is why it is easy to
cook tender thinly sliced well done beef, very hard to cook a steak,
impossible to do it with a solid chunk.