Ingredients

about 4-7 pounds beef marrow, knuckle bones, rib bones, or soup bones (source from Whole Foods, your local Farmer's Market, or health food store found in the freezer section)
4 or more quarts cold filtered water
½ cup apple cider vinegar
3 onions, coarsely chopped
3 carrots, coarsely chopped
3 celery stalks, coarsely chopped
½-1lb mushrooms (optional)
1 teaspoon dried peppercorns, crushed
1 bunch parsley
2 bay leaves
2 cloves of garlic (smashed)
1 strip kombu or 2 tablespoons any variation of sea veggies
Sea salt and Black Pepper

Instructions

Place bones in a large Instapot with vinegar and cover with water. Let stand for one hour. Meanwhile, place any reserved meaty bones in a roasting pan and brown at 400 degrees in the oven. When well browned, add to the pot along with the vegetables. Pour the fat out of the roasting pan, add water to the pan, set over a high heat and bring to a boil, stirring with a metal whisk to loosen up coagulated juices and brown bits stuck to the bottom. Add this liquid to the pot. Add additional water, if necessary, to cover the bones; but the liquid should come no higher than within one inch of the rim line indicated inside the pot, as the volume expands slightly during cooking. Seal your Instapot lid and set it for “Soup” setting.
Remove lid, turn Instapot off and allow to cool before removing bones with tongs or a slotted spoon. Strain the stock into a large bowl. Let cool in the refrigerator and remove the congealed fat that rises to the top. Transfer to smaller containers and to the freezer for long-term storage.