Far more popular and widely accepted is to simmer bone broth for anywhere from 18 to 36 hours; but I will argue it's not the best way. According to this study, pressure cooking preserves more beta-carotene and ascorbic acid in veggies compared to cooking over the stove for a longer time. And this study shows more preservation of Vitamin C with pressure cooking broccoli than boiling or steaming it. This suggests that high pressure cooking for a shorter duration retains more nutrients than simmering for an extended period of time. So not only is pressure cooking bone broth quicker, it's more nutritious. I'd say that's the way to go.