I cut the fat into pieces, put them in a stainless steel bowl and steam them. Some of the tallow melts out and then I sieve the rest.
If I want cracklings (especially good from pork fat) I cut the fat into strips and put them in a crock pot under low (high is OK too since it never gets too hot) and let the fat render out also leaving me with crispy cracklings...the best food there is!

Add the coursely chopped fat, whatever fat you have, to either a cast iron pot or a heavy-bottomed cook pot. A cheap, thin-bottomed pot will likely burn the fat.

Add water up to about 30% to 50% of the top of the fat.

Turn heat on high until water begins to simmer/low boil. Reduce heat so the water just simmers. This will get the rendering started without burning anything. Now go away and read a book or paint a picture or whatever.

Occasionally look in the pot. When the water is gone, or almost gone, reduce heat just so some bubbles are still being produced. Go back to book.

Look at pot. If water is gone and melted fat is being produced adjust heat so a cooking thermometer shows a temperature of 180F. As more fat is produced reduce temperature to 160F.

As long as there is enough heat to cause the trimmings to bubble, rather like bacon in deep fat, then fat is being rendered.

As the end draws nigh, the fat and meat particles will be turning brown. Remove from heat and using a slotted spoon remove all the trimmings you can. If the trimmings continue to cook, they will burn and the fat will taste burned. DO NOT LET THE TRIMMINGS GET TOO BROWN. THE MORE BROWN THE TRIMMINGS, THE DARKER THE RENDERED FAT. IF THE TRIMMINGS ARE TOO BROWN, THE RENDERED FAT WILL TASTE OF OVERCOOKED MEAT. If you remove the trimmings before they turn brown, the renderings will be clear when melted and white when cool. Browned trimmings will add a golden color and a light flavor to the renderings. The browner the trimmings the more golden the color and heavier the cooked meat flavor.

My renderings are a light golden color and lightly smell of browned meat. Back when I was eating biscuits and gravy, this fat with the very light flavor of cooked meat gave the biscuits and gravy a background flavor that was unbeatable.

Allow to cool, pour into a storage container, tightly cap it, and store in a cool spot. There may be a bit of water in the bottom of the pan if you have not completely cooked it off. Be sure none of it gets into the storage container.

After 24 hours look at it and if any moisture is on the surface of the hardened fat, wipe it up with paper towel.

This may read as complicated but it's not. Just use the minimum amount of heat to get the job done and keep an eye on the process. My grandmother used to render the fat from several hogs at a time. She would start the process then move to other chores while the lard rendered. It ain't no big deal. Just be patient, sez Granny.

hate to leave just a link:

http://www.cheeseslave.com/2009/07/09/how-to-render-lard-tallow/

but cheeseslave really knows her stuff.

Art's correct. That method works fine.

I started out grinding the suet through the grating attachment in my food processor. I did that until the suet snapped that attachment. Woops, Plan B. Next, I cut my beef suet by hand into half-inch cubes. Better idea; good arm workout, too.

Then, I tried two rendering methods to see which was more effective:

(1) I turned my stove on to medium low and tossed the suet into a large frying pan. I let the fat render until the cracklins (depleted bits of suet) were a deep brown with a crispy texture. This required a fair amount of stirring since I have a "stick" frying pan.

(2) I turned the oven on to about 200F and tossed another batch of suet into a stock pot and just let it go without any TLC for about an hour.

The end result for both was (drumroll) lots of tallow. No surprises, no mistakes. All in all, I would have to say that the oven method was a little easier if only because I didn't have to stir.

To render for tallow, cut fat into 1-2" pieces, freeze, then run through grinder. Add ground fat to saucepan with a little water to loosen it up. Bring to a boil and simmer until all thats left are crispy bits of meat and fat. All the water from the fat and what you added will have evaporated. Strain and enjoy.