In an 8-quart stock pot, combine the turkey bones, carrots, celery, onion, parsley, thyme, garlic and black peppercorns. Add cold water to reach 1 inch below the rim of the pot.
Bring to a boil over high heat. Reduce the heat to medium-low. Skim any white foam off of the surface of the stock and discard.
Simmer for 3 to 4 hours. Adjust the heat between medium and medium-low to maintain a low simmer. (You do not want to boil the stock rapidly or it will be cloudy.)
Remove the pot from the heat and let it cool for 30 minutes to 1 hour. Using a spider, remove the bones and any large vegetable pieces from the pot and discard them.
Strain the stock through a fine mesh strainer.
Let the stock cool completely before placing it in airtight containers. It can be stored in the refrigerator for up to five days.
Notes
Use kitchen shears to snip the turkey carcass into manageable pieces. This way, all of the turkey bones will fit in the pot and can be submerged in the water during simmering.
Save vegetable scraps for stock! If you're prepping a big holiday meal, save those garlic, onion, carrot, and celery trimmings used for other recipes and toss them in the stock pot. I like to keep a freezer bag, add scraps to it when I have them, and use it when I make stock.
Line the fine mesh strainer with cheesecloth before straining to remove as many small particles as possible. This is optional but will result in the smoothest, clearest stock.
Use this technique to make chicken stock! Use 2 to 3 chicken carcasses (freeze them as you acquire them), then make a batch. Or use 3 lbs of chicken wings or legs.
Add other seasonings: You can a bay leaf, squeeze lemon rind, sliced ginger, or other herbs like rosemary, sage, and oregano to season your stock just how you like it.