"True" schmaltz vs chicken soup fat?
As I understand it, "true" schmaltz is made from saving all the little pieces of chicken fat and skin you can, then cooking them down to render the fat. The liquid fat, which will harden, is the schmaltz, and the crispy bits that are left are the gribbens. Right?
Although I've never done that, I do make homemade chicken soup often, and I always refrigerate it then take off the solidified fat at the top and save it for my matzo balls, etc. Is this the same as schmaltz which has been rendered? Or does rendered fat have more flavor because of being essentially fried rather than boiled? I think that sometimes, when people render schmaltz, they put onions in for extra flavor, too. So, I've always wondered -- Is my chicken soup fat schmaltz?
The fat from the soup will a) be flavoured by the other components of the soup (onion, carrot, celery, peppercorns and so forth, and b) still contain a fair amount of water -- so it will "pop" and splatter when it hits a hot pan.
Rendered fat will taste much "cleaner" and cooks more cleanly, too.
I save both kinds -- just store them separately. I dedicate a whole corner of my fridge to an embarrassment of animal-fat riches. I love that I can open the fridge and have not only duck fat, but my CHOICE of duck fat. So nice. ;)
+1. Yes, it spatters if you use it for frying but in doing so, it rids itself of the water, making it quite similar in taste to schmaltz. I've made schmaltz with onions - the color and flavor are a bit deeper but IMO not worth a special effort. My chicken-stock fat has been flavored with onion, carrot, and celery, and I have never used it for frying anything that didn't involve frying onions as well, so I don't need schmaltz.