Tallow is from cow fat, lard is from pig fat, schmaltz is from chicken fat (or turkey). Rendering fat is the process of extracting the fat from the raw fat, basically cooking fat, to make, well, fat. These are healthier than vegetable shortening, palm oil, since they are naturally occurring, not heavily processed from vegetables.
Tallow is stable at higher heat than lard. The best fish and chips, always cooked in tallow. Tallow and lard can be used for any recipe calling for shortening. Tallow can be used for deep frying. Schmaltz can be used for frying eggs, potatoes, etc.
The steps are the same for tallow, lard, and schmaltz.
You need fat. If you have a local butcher, you can get cow fat from them when a cow is slaughtered, for pig fat, just go to a larger Tesco, it is sold there. Yes, Thais still render lard for cooking.
Refrigerate the fat overnight, easier to work with when it is cold.
Next step, you need to cut away any bits of meat, gristle, veins, etc. Bits of meat left on is not a show stopper by any means.
Now cut the fat into small pieces and put the fat into a slow cooker, which is much easier to control the temp than a stove top stock pot. If you do not have a slow cooker, use a large stock pot, but remember, DO NOT burn the fat, that is not pleasant!!! So try and use a slow cooker.
Set the slow cooker on Low setting, uncovered as you want the water in the fat to evaporate leaving just the fat. If using a stove, you want the lowest amount of heat from the burner, again, this is not something you want to burn!
As the fat cooks, the fat want will be a clear liquid, the chunks of fat float on the top and will shrivel and crisp up. When the chunks of fat have reached the smallest size, meaning they are getting any smaller, the rendering is done.
Now you need to strain it, you need a colander, cheesecloth (or a towel, sheet, etc.). You can do this two ways, into jars or into a baking dish lined with wax paper. As the liquid cools, it will turn a yellowish white color and will solidify.
Store in the fridge or even the freezer.
Schmaltz addition was inspired by good friend, Hans Schmidt.