There is no comparison to the flavor of homemade broth. Roast the turkey parts and vegetables, then make the broth. Make ahead and freeze for using Thanksgiving Day for gravy and afterwards for soup.
OR a large heavy duty disposable aluminum pan works You may need to double them up for strength or place the pan on a rimmed baking sheet pan for support. Dispose of after use.
Pre-heat oven to 375° (190 c) and get out a large roasting pan. Remove as much skin and any extra fat that you can from turkey pieces. Place pieces into the roasting pan in a single layer.
Prep veggies and roast
Roughly chop onions, carrots and celery. Split garlic head horizontally through the center (no need to peel). Add vegetables and garlic to the roasting pan with the turkey. Place pan in the oven and roast for 1 hour. At the end of the hour, add the wine and roast another 30 minutes.
Make the broth
Place roasted turkey and vegetables into a large stock pot (10-12 quarts). Add bay leaves, parsley, thyme, peppercorns and cold water. Bring the pot to just under a boil, turn down to low and barely simmer for 10-12 hours. You want the pot to be at a slow, gentle bubble to extract as much flavor as possible. When the water level drops about 2", add a little boiling water from a tea kettle, keeping the ingredients just under water.
At the end of 10-12 hours, remove all meat, vegetables, herbs and discard, as they will be spent. Drain broth through a fine sieve into a clean large pot or bowl. Place in a sink filled with ice and cold water to cool quickly. Place pot on a trivet or small rack to help water circulation under the pot for faster cooling. Stir occasionally. You want the broth to cool as quickly as possible for food safety.
When stock is cool, below 70°, cover and place in the refrigerator. The next morning, remove any fat solidified on top, place into containers, label and freeze.
Notes
To thaw broth, place containers from the freezer into the refrigerator for 24 hours and thaw slowly. Alternatively, place frozen containers in a sink with cool water to start the thaw, then place semi-frozen broth into a pot and heat over low until liquid, or use the microwave at low power.Do not leave broth out on the counter to thaw at room temperature as this is not food safe.