When I need schmaltz for baking, I make it the following way, using the fat
and skin from the chickens:
Place about a cup's worth of skin and fat, diced or ground small, in 2 cups
of cold water. Bring to a boil, and simmer, stirring frequently, skimming
as needed, until the water has been reduced by half. Strain into a clean
glass container. Using a wide-mouthed pint jar is great, as you can see
about how much fat you've rendered out. Place in fridge. When the fat as
set, remove it from the liquid, place in whatever container in which you'll
be using, and freeze. The liquid is now chock-full of collagen from the fat
and skin, and should be nicely jellied. You can use it when making stock;
it adds body and protein. Not much flavor though.
Now, as far as what you've saved from your chicken soup, if it's just as
bland and plain as what you've gotten from the skin and fat, you can freeze
it right along. You might want to premeasure it in useable portions before
freezing. I use it for the crust of my Thanksgiving Apple Pie; since the
main meal is a meat meal anyway, why not? I like the results better than
butter or Veg. shortening, and from what I have read not only is it lower
in saturates (though higher in outright cholesterol) it has lineolic acid,
which I have read helps the body break down the "bad" cholesterol.
I figured out to use it for crusts from a Shaker cookbook. They spoke
highly of chicken fat as a pastry shortening.
From: Blanche Nonken in rec.food.preserving