Maybe more a "Home Cooking" question, but maybe not. I routinely save duck fat for rendering when I get the chance. I've heard some people do that with chicken fat, and, of course, bacon fat.
Now I'm looking at quite a bit of beef fat that congealed on top of a beef stock (from meaty bones and shanks) after cooling, and I wonder why I always throw that out, and also pork fat apart from bacon?
Uses for various fats, or cautions?
That's tallow (the rendered fat of cattle or sheep is tallow; unrendered, it's suet). If it's from grass-fed beef, it's actually a "healthy" fat (you can even tell by looking - grain-fed animals give off white/off-white fat, while grass-fed fat has a more greenish-yellow color); if not, you should probably avoid too much if cholesterol is an issue. Traditionally used in mincemeat and savory pie crusts. Or for Yorkshire pudding or frying fish and chips.
If you wish to purify it for longer keeping, btw, melt it and put it in a jar with some water; shake and refrigerate. Then, when hard, drain off the water and cut off the impurities along the edge that faced the meniscus of the water. The mixing with water helps to capture the impurities along the meniscus.
I've started saving all my animal fats. I use beef fat for whenever I'm cooking beef. For example, yesterday I seared a steak. Butter is tasty but it burns. So beef fat. Makes sense in my mind. I also use it even if beef is not the star. I stir fried rice noodles with bean sprouts, onion, thai basil, and sliced beef. I used beef fat in the wok.
A roux for a chicken soup? Chicken fat. Saute mirepoix for beans? Pork fat.
I love frying red potatoes in duck fat for breakfast. My wife freaks out but I have read that it is a healthier fat than butter.
Thanks for the tips!
This time, I think I will try to make bird food for the hungry feathered things out there this cold winter.
I save it and use it anywhere it seems like the flavor would work. When I skim it off of stock or stew, though, I usually try to use it fairly quickly or freeze it, since it typically contains some moisture or other impurities. With pure fat (bacon, rendered lard, schmaltz or duck fat) I just put it in the fridge, where it seems to last basically forever.