Preheat your oven to 400 degrees F. Spread the beef bones on a baking sheet in a single layer. Roast for 30 minutes, flipping halfway through, until the bones are deeply browned. This step builds an incredible depth of flavor in the finished broth.
Transfer the roasted bones to the Instant Pot. Add the apple cider vinegar, quartered onion, celery, carrots, garlic, peppercorns, bay leaves, thyme, and salt.
Pour in the cold water until the pot is filled to the max fill line. The vinegar helps draw minerals from the bones, so do not skip it.
Lock the lid and set the valve to sealing. Pressure cook on high for 120 minutes.
When the cook time is complete, allow a full natural pressure release. This can take 30 to 40 minutes. Do not rush this step.
Remove the lid and carefully discard the bones, vegetables, and herb stems using a slotted spoon. Strain the broth through a fine mesh strainer into a large pot or heat-safe container.
Let the broth cool slightly, then taste and adjust the salt if needed. Store in jars in the refrigerator for up to 5 days, or freeze for up to 3 months. As it chills, a layer of fat will solidify on top, which can be removed or stirred back in.