Optional Flavor Enhancing Step: Toss turkey bones & carcasses with 2 tbsp olive oil. Roast them in a preheated 450°F oven until browned (about 30 – 45 minutes).
Prepare Instant Pot: While the bones are roasting in the oven, heat up your pressure cooker (Instant Pot users: press Sauté button and click Adjust button to Sauté More function). Make sure your pot is as hot as it can be (Instant Pot: wait until indicator says HOT).
Sauté Onion and Garlic: Add 1 tbsp (15ml) of olive oil. Then, add diced onion in the pressure cooker. Sauté for roughly a minute until soften. Add minced garlic and sauté for another 30 seconds until fragrant.
Sauté Celery and Carrot: Add in chopped celery and carrot. Sauté until the vegetables are slightly browned (roughly 10 minutes). At the 5 minutes mark, add in 1 tsp (3g) whole black peppercorn, all the herbs, and 2 bay leaves into the pressure cooker.
Deglaze: Add ½ cup cold water in the pressure cooker and deglaze by scrubbing the flavorful brown bits off the bottom of the pot with a wooden spoon.
Pressure Cook Turkey Stock: Add all the roasted turkey bones and 9.5 cups (2.375L) cold water into the pressure cooker. If you are using apple cider vinegar, add in 1 tbsp (15ml). Close lid and pressure cook at High Pressure for 45 - 60 minutes + Natural Release. Open the lid carefully. Full Natural release will take roughly 1 hour. You can do a 30 minutes natural release if you like.
Strain & Store Turkey Stock: Strain turkey stock through a fine-mesh strainer. Let it cool to room temperature and refrigerate overnight. Skim off the layer of fat on the surface of the stock.