Thoroughly clean the bones.
Set IP on SAUTE and start. Add all the bones in the IP pan and fill it with water. Bring to a running boil. Discard the water.
Transfer the bones to a baking dish. Add peppercorn, celery, carrots and onions. Sprinkle with salt and pepper. Broil in the oven for 30 minutes.
Transfer everything in the IP pan and fill water to the max level. Add bay leaf, thyme and add more salt and pepper.
Set IP on PRESSURE COOK for 100 minutes and do NPR. Let is soak overnight and boil again for 30 minutes. Do NPR and cool to room temperature.
Strain the broth and store in broth. Keep refrigerated.
