I took the hard fat from my deer and rendered it down to make tallow. Tallow is hard like wax and can be used for all sorts of things from candles to wood, bone and leather preservative. You can use it to waterproof your boots or make soap. You can cook with it. Rendering is a process which takes fat which would otherwise go rancid and removes impurities, this keeps it from going rancid.
The first thing you need to do is remove the hard fat from your deer or other animal. Fat from deer, sheep, beef and bison is considered tallow while fat from pigs is considered lard. Lard is much softer than tallow, but the process is the same for either.
Next, I cut mine into 1" or so cubes. Now is the time to remove any chunks of meat, tendon or the like that you don't want in the mix. I removed the large chunks of meat, blood, tendon and sinew and left the rest.
This next step is optional, but should speed up the rendering process. Grind it up!
I also weighed mine to get an idea of how much fat and such it takes to make a pound of tallow. If I recall correctly I had just over 1-3/4 pounds of fat and scraps.
There are three ways to go at this point. I chose to boil because it is safer and prevents overheating. I added it to a pot and added just enough water to cover it.
Bring it to a boil and immediately reduce to a simmer. Let it simmer until the fat oozes out, 1/2 to 1 hour should be plenty of time if you grind it. I let mine go for 1 hour. If you didn't grind you will probably want to use a potato masher or the like to squish out the fat from the chunks as it simmers. Don't let it boil over or slop out, it will catch fire and/ or splatter if it hits the burner.
Once you feel all the fat has seperated immediately strain it through a fine a mesh strainer. Don't let any go down the sink or it will plug it up and be careful not to burn yourself. If you haven't ground the fat you'll want to squish the bits with the potato masher to get the remaining fat to run through.
The strainer bits can be fed to the birds, cats, or dogs. They'll love it. If the fat was fresh you can eat it yourself. If you had simply fried out the tallow without water and without grinding you would now have cracklins. People eat this stuff. I tasted some and it had no real flavor and was the consistency of overcooked hamburger.
Now, let it cool off to room temp and refrigerate overnight. You actually don't have to refrigerate it, but it goes quicker if you do.
In the morning you'll have this...
Slide a knife or something down beside it to loosen and lift it out. Mine was already loose so I just reach in and grabbed it. It weighs about 1-1/2 pounds now.
As you can see, it will have some grizzle/ cracklin bits that made it through the colander on top, and loose bits on the bottom. Rinse it off with cold water. Some bits will stay, that's ok. By the way, hot water will melt it. Dry it off completely with a towel.
Now you can get rid of the water and bits that settled out. I wouldn't put them down the sink, but feed to the dogs or cats. It is full of nourishment that they otherwise would not likely get. It's essentially a really rich beef or, in this case, venison broth.
Now, break it up into a small pan, place that pan in a larger pan filled partway with water. Let it melt. Be careful not to boil the water over and watch out for splattering from any moisture left in it. It will burn you. Let it go until any retained moisture is evaporated off. Be careful not to spill the meted tallow, it will ignite if it hits the burner.
Let it cool slightly and pour it through a coffee filter into a dry heat safe container to get rid of the small bits that didn't settle out earlier. It needs to be pretty warm to run through the filter, don't burn yourself or melt the filter. If you pour it into glass that is wet or not heat safe it will likely break the glass. I use dry canning jars.
Let it set up once more and it is now rendered safe, it will not go rancid. If you used sterilized equipment you can supposedly let the jars seal and store it in the cupboard. I'm storing mine in the refrigerator.
Now you can make candles and stuff. Here, I used a sliver of false tinder fungus as a wick and added some Nutmeg and vanilla to give it a pleasing scent. It has a lower melting point than wax, your body heat will melt it. But, if filtered well it burns fairly clean and long with no noticable scent.
That's it! Here's a video that shows the entire process. It's real easy to do, but you have to be careful not to burn yourself or catch something on fire.