The eggshells will still be mostly white or brown, but might have a light tint, which is okay. Baking eggshells any longer can produce an unpleasant smell. • Allow the eggshells to cool, then grind in a blender or clean coffee grinder for 1 minute, or until you achieve a very fine powder with no sharp edges. read more
I cook for my dogs and use ground egg shells to balance the meat. I grind the egg shells to get accurate measurement of calcium. One teaspoon of ground egg shell which is about one egg shell, will give 2000 milligrams of calcium. As I feed three dogs with weights from 10 to 50 pounds, I find the teaspoon measurement easier. read more