1. Pour the cold water into a large stockpot and add the chicken scraps.
2. Halve the onion and garlic, leaving the skin on, and add them to the pot.
3. Cut the celery and carrot into three or four large pieces and add to the pot.
4. Toss in the cloves and peppercorns.
5. Turn the heat to medium-high and bring the stock to a lively simmer. Do not boil it, however, or it will become cloudy.
6. Notice that scum floats to the surface as the stock begins to simmer. Remove these proteins with a slotted spoon.
7. After skimming the stock, reduce the heat to medium-low and simmer for 3 ½–4 hours. When the stock is intensely flavorful, it’s ready.
8. Remove the bones and discard.
9. Cool the stock to room temperature, then strain through a large sieve.
10. Refrigerate overnight, then remove and discard any fat that has risen and solidified on the surface.
11. For convenient storage, freeze stock in small portions in ice cube trays or zip-lock bags, then thaw just what you need for everyday use.