Having rich homemade stock on hand allows you to make a delicious soup on short notice. Freeze in small containers so you can defrost only as much as you need.
Put all ingredients in a large stockpot. Bring slowly to a boil, skimming foam often. Reduce heat and simmer for 4 to 5 hours, skimming occasionally. Keep flame very low, and do not allow stock to boil.
Strain stock through a fine mesh strainer lined with cheesecloth. Discard solids. Refrigerate overnight and remove fat.
For a more concentrated flavor, reduce as needed.