In a large soup pot or Dutch oven, place turkey carcass (take the remains of the turkey after it has been carved and break it into pieces so it will fit in your pot; cover with cold water by at least 1-inch). Add carrots, celery, onion, garlic, and red pepper (optional) to the soup pot. Add any other vegetables that you like, if desired.
Cover pot and slowly bring to a simmer. As soon as you start to see boiling occur, immediatly reduce heat to low and skim off any scum on surface. Scum is the filmy layer of extraneous or impure matter that forms on or rises to the surface of a liquid or body of water. Cover pot and let slowly simmer approximately 3 hours.
TIP: The key to a good stock is to bring the water to a boil just once at the beginning and then lower heat and cook at just barely a simmer for the remainder of the cooking time, as long slow cooking is best to extract all the subtle flavors. Do not let the stock reach a rolling boil!
After cooking, remove from heat and discard all the turkey bones, meat, and vegetables (since your have cooked the mixture for a long time, there is no nutritional value left). Strain the remaining liquid to remove smaller particles in the stock (pour the liquid through a fine mesh sieve placed over a large pot).
Place strained stock into shallow containers and refrigerate immediately. Refrigerate soup stock overnight and skim any congealed fat from the surface in the morning. The juice will gel up after being refrigerated, but will dissolve when stock is reheated later. This is because of the natural gelatin in the turkey bones.
The stock will last for about a week in the fridge. You can freeze the cooled stock and it should maintain taste and quality for about 4 to 6 months.
You now have the most wonderful low-fat turkey stock to use in making a delicious turkey soup or to freeze for later use.
How to keep homemade turkey stock from getting cloudy:
Skimming the scum that comes to the surface during the first 30 minutes of simmering and not letting it boil seems to help prevent clouding. The rule is - Skim early and skim often.
Always simmer your stock and do not let it boil. Not boiling also leads to a richer tasting stock. Furious bubbling breaks up particles and causes clouding also. Simmer for approximately 3 hours total. I also think that simmering the stock too long contributes to making it cloudy.
Refrigerate stock overnight or until all the fat raises to the top. Then remove the fat.
There is also the old egg white trick (I have never tried it). Add unbeaten egg whites to the stock and let it simmer slowly, so that the cloudy particles stick to the egg and you can strain it out.
Once the stock is finished cooking, let it cool in the refrigerator. Skim off the fat if needed. Remove the carcass or bones. Strain the broth well.
Take a strainer basket or steamer rack and insert into the inner pot. Place the chopped vegetables,herbs and seasonings into the basket or strainer. Next layer the turkey bones and carcass over the top of the vegetables. Try to compact the bones close together.
Pour cold water over the top of the vegetables and bones until the bones are just barely covered. Adjust the amount of water added to make sure the inner pot is no more than 2/3 full or it may have trouble coming to pressure. Note: the trick to making a good stock is to not add too much water. you only need just enough to cover the bones. If too much water is added, then the stock may not gel up after cooling. All the good nutrients are in the gelatin! If you run into that issue, then you may need to let your stock simmer on the stove uncovered until the contents cook down more.
Place the lid on the Instant Pot and close to seal. Next, make sure the pressure valve is closed to the sealing position. Press the Manual button, with a high-pressure setting. Adjust the cooking time for 120 minutes. When the cooking time has finished, allow to Natural Pressure Release until you see the pressure pin drop down. (This may take 20-25 minutes since there is a lot of liquid in the pot.)
Place silicon oven mitts on your hands to protect from the steam and heat. Lift out the colander or steamer basket and discard the turkey bones and vegetables. Next, pour the stock through a strainer into another large heat-proof bowl. You can repeat this step until the stock is nice and clear.
Let the stock cool down. As the stock is cooling you can skim off visible fat floating to the top and discard.
Once the stock has cooled down enough( about 2-3 hours) cover and refrigerate until ready to use.
The turkey stock can be refrigerated up to 3 days in advance of using. If not planning to use the turkey stock within 3 days, place in the freezer until ready to use. Whether the stock has been refrigerated until cold or stored in the freezer, there will be a thin layer of fat that has congealed on the top. Remove that by scraping it off with a spoon before you cook with the stock. Discard the congealed fat but be careful not to scrape off any clear gelatin. I usually refrigerate my turkey stock and skim off the fat before using in my soup making.
* Strip the turkey carcass of any large usable pieces of meat; set turkey meat aside and refrigerate until ready to use in your soup. Do not add the giblets.
** Enough cold water to cover all the ingredients in the pot by at least one (1) inch.
Homemade Turkey Stock Recipe: https://whatscookingamerica.net/poultry/turkeystock.htm