Beef fat (optional)
Put everything in the pot and simmer for approximately 48 hours. Remove the pot from the heat and strain the stock through a course strainer first to remove the bones, meat and veggies. Save the bones if you want to make bone meal. Strain the stock a second time through a mesh strainer and then again through a fine muslin cloth (I use a new chux that I discard afterwards). Once this has settled, scoop the fat you can and freeze in silicone ice cube trays. Put the stock in the fridge to cool
Once cooled you can separate the remainder of the fat to melt and freeze in ice cubes or melt and put in a jar. Note that the tallow only lasts about 2 weeks in the fridge. The stock should be jelly consistency when chilled. I freeze this to use as needed in the future. I usually freeze it in a combination of ice cubes and larger quantities so that I can get out what I need depending on the recipe. It only lasts about 1-2 weeks in the fridge.
If you are making bone meal take the bones and put them in a pressure cooker and cook in water for approx. 3 hours. Check to see if the bones are soft enough to cut up, if they are put them in the blender. If not cook them longer in the pressure cooker. Once the bones are blended put the mush in a dehumidifier or the oven on low heat if you do not have a dehumidifier like me. The soggy bone mush smells a lot like cat food. Once the water has been taken out of the bone meal sift it and put the pieces that are too big back through the blender to pulverise. You can now use this powder in the garden or as a calcium and potassium supplement.