Place the bones in a large stock pot with water and vinegar. Let sit for 20-30
minutes in the cool water (the acid helps make the nutrients in the bones more
available).
Rough chop and add the vegetables (except the parsley and garlic, if
using) to the pot. Add any salt, pepper, spices, or herbs, if using.
Bring the broth to a boil. Once it has reached a vigorous boil, reduce
to a simmer and simmer about 8 hours. During the first few hours of simmering,
you'll need to remove the impurities that float to the surface. A frothy/foamy
layer will form and it can be easily scooped off with a big spoon. Throw this
part away. Check about every 20 minutes for the first 2 hours to remove this.
Grass-fed and healthy animals will produce much less of this than conventional
animals.
During the last 30 minutes, add the garlic and parsley, if using.
Remove from heat and let cool slightly. Strain using a fine metal
strainer to remove all the bits of bone and vegetable. When cool enough, store
in a gallon size glass jar in the fridge for up to 5 days, or freeze for later
use.