Place your turkey carcass into a very large stock pot (at least 6-quart capacity.) Add in your turkey neck, giblets, any skin, and leftover turkey drippings, if you have them. It’s okay if you don’t, you will still get a great turkey stock from just the carcass.
Add the onion, carrots, and garlic. Chop off about a third of a head of celery, the end that has the leaves preferably, but use what you have. You should have several short stalks. Add them to the pot.
Add a bunch of parsley, half a bunch of sage, 3-4 sprigs of rosemary, and about 5 sprigs of thyme.* Tear the herbs up a bit so they start releasing flavor faster.
Add 3 bay leaves and 8-10 peppercorns.
Cover the turkey and vegetables with about 4 quarts of water, or however much you need to submerge everything in the pot (at least mostly, some parts sticking out is okay.)
Bring to a rolling boil over high heat. After if has come to a rapid boil, turn the burner down to just below medium, or wherever you can maintain a low simmer. There should be gentle bubbles but nothing too active.The liquid should be gently moving at all times, not still.
Simmer for about 2-4 hours. Check on it every now and then, and skim off any foam or scum that may settle on the top. If your water is boiling off too quickly and the bones start to stick out of the water, add more water to cover it up, and bring back to a simmer.
Pour the stock through a colander into a large bowl (or two), catching any bones or vegetables.
Wait for the stock to cool (or refrigerate/freeze it) and skim the fat off with a spoon.
Allow stock to cool before moving to an airtight container and placing in the fridge or freezer. I like to use mason jars if you plan to store in the fridge, or quart size ziplocks if you plan to freeze. Stock can be stored in the fridge for up to 5 days, or in the freezer for about 3 months.
