Heating gelatin. Consequences?

Ryuji wrote:

>
>
>Gelatin doesn't go bad just by heating to 140F (=60C) once. It would
>be worse if you repeat heat-cool cycle. Some modern sauces use gelatin
>in combination with or in lieu of other traditional stuff like roux,
>starch, etc. Those sauces should not be reheated too many times or the
texture will be off.

The setting properties of gelatin are not lost by just heating it to
140-160F, *if* it does not stay at that temperature for too long.
What is too long? More than 4-6 hours in my experience. In preparing
carbon tissue I add the pigment and other things to the warm gelatin
solution at about 130F and then allow the pigmented solution to stay
in a warm water bath for an hour or so for the bubbles to dissipate
before using it to coat tissue. If used within a couple of hours the
gelatin retains all of its setting properties. However, if the
pigmented gelatin stays in the water bath at 130F for more than six
or eight hours the gelatin definitely loses some of its ability to
set. I have observed this in quite a number of instances so there is
no doubt in my mind about the fact that prolonged heating does break
down gelatin. And this applies to both porcine and ossein source
gelatins.

Sandy
Received on Fri Nov 12 09:38:04 2004