These photos will show exactly how I render fat. In this example it is pork fat, but the principle is the same for all fats. The fat is cut into 1-inch/2.5cm pieces. You can cut them smaller and speed up the process slightly. Water is added about 1/3 cup /75ml per 1lb /450g of fat . I have about 2.6 lb /1.2kg of fat here so I added just over 1 cup/250ml. Now it
goes in the oven at 250F/120C.
This is the pan after 30 minutes. You can see the fat has melted a bit and you can see the water in the pan. It pays to have a thermometer in your oven they are not always accurate at low temperature.
Now 2 hours later (2 1/2 hours since the start). The fat is melting but there are still big pieces. Stir the fat and press the larger pieces against the side of the pot so they break up
Another 2 1/2 hours have passed (5 hours total). Note the fat is not all melted.
Here it is 2 hours later. This is the time to strain before the fat starts to colour. This has taken 7 hours.
Here is the fat in a very fine strainer over a glass-measuring cup. As you can see there are only a few lightly coloured pieces. Once the fat is drained you can return these fat pieces to your pan and continue to render. You will obtain a little more fat but it will be stronger in flavour.
Here is a wonky view of the fat in the measuring cup. My fat yielded a little over 4 cups/1l. It was also clearer the flash has added a golden tone.
Here it is chilled and you can see it is creamy white, perfect for everything from pastry to deep-frying.
I turned the glass upside down to show you that you will probably get some deposit that shouldn't be left with your fat. It could be used in a pork dish; it is a light pork jelly.
That's it very straight forward. All you need is time, and to look at the fat from time to time and, most importantly make sure your oven is not too hot.