Homemade Chicken Stock

1. Gather all the ingredients. If you‘re using frozen chicken, make sure that it‘s completely defrosted.  
2. Rinse 4 lb chicken backs and necks quickly and soak in cold water for 30 minutes. Replace the water several times. This helps to remove blood.
3. Slice 2 inches ginger (keep the skin on), cut 3 green onions/scallions in half lengthwise, and smash 1 clove garlic. Tip: As you can see in the images, this time I used 2 Tokyo negi (Japanese long green onion) and 2 green onions. I think the green part was too much. While the stock tastes fine, it lacks a golden color. I‘d recommend sticking with the recipe calling for 3 green onions.
4. In a stock pot, bring water to boil. Add the chicken and cook for just 20 seconds. Immediately drain.
5. Under cold running water, clean the chicken bones very well. Use your thumbs to go in and remove any blood or offal that might be attached.  
6. Chop the bones into 2-inch (5-cm) pieces. This helps the flavors come out better from bones.
7. Place the clean chicken and 4½ QT water (4 L, 17 cups) in a stockpot. Bring to boil over high heat. Prepare a fine mesh skimmer and water in a 2-cup measuring cup for cleaning the skimmer (this a helpful trick).
8. Once boiling, immediately reduce heat to bring the stock to barely a simmer. If you boil on high heat, the stock will be cloudy. Next 15 minutes or so, skim the scum and foam on the surface with a fine mesh skimmer. It‘s tedious work but it helps make better stock. 
9. Once the stock is clean and there‘s nothing left to skim, you can now add ginger, green onion, and garlic. 
10. Continue to cook for 3–6 hours (or you can pressure cook for 40–45 minutes). This time, I was running out of time, so I cooked for 2½ hours but it still tasted amazing.
11. Pick up the bones and other solids with a skimmer or slotted spoon. Then, pour the chicken stock into a fine-mesh sieve over a large bowl.
12. The chicken stock is ready to use. Season with kosher salt as you like. For later use, divide the stock into mason jars and allow to cool uncovered. Keep the oil on top and once the oil is solidified, you can decide to use it for cooking or discard it.  

To Store

1. The stock will last up to a week in the refrigerator or in the freezer for several months. Just be sure to leave enough headspace (2 inches, 5 cm) for the stock to expand.