Tonkotsu Ramen Pork Bone Broth

Thoroughly rinse the pork femur bones and trotters under cold running water to remove any impurities. Place them in a large stock pot, cover with cold water, and bring to a rolling boil over high heat. Boil vigorously for 10-15 minutes, skimming off any scum that rises to the surface. This blanching step is crucial for a clean tasting broth.

Drain the blanched bones and rinse each piece thoroughly under cold water, scrubbing away any remaining dark scum or bits. Clean the stock pot as well. This meticulous cleaning ensures your Tonkotsu broth will be pure white and free of off-flavors.

Return the cleaned bones to the clean stock pot. Add 6-8 liters of fresh cold water, ensuring the bones are fully submerged. Bring the water to a rapid boil over high heat, then immediately reduce the heat to a strong, rolling simmer. The water should be bubbling vigorously but not overflowing.

Maintain the strong simmer, adding more hot water as needed to keep the bones fully submerged throughout the cooking process. Skim off any fat or scum that rises to the surface regularly. Continue this vigorous simmering for at least 6-8 hours, or until the broth starts to turn milky white.

After 6-8 hours, add the roughly chopped green onions, sliced ginger, halved garlic head, and quartered onion to the pot. Continue to simmer vigorously for another 6-10 hours, constantly monitoring the water level and adding hot water to maintain volume and keep bones submerged. The goal is to emulsify the fat and collagen, creating the signature creamy texture.

Once the broth is deeply milky white and the bones are soft and crumbly, remove the pot from heat. Carefully strain the broth through a fine-mesh sieve, pressing on the solids to extract all liquid. Discard the bones and aromatics. Season the pure Tonkotsu broth with a pinch of salt if desired, but typically it is seasoned with tare when assembling the ramen. Allow it to cool before storing or using.