Tonkatsu Broth Recipe

Trim and rinse

Rinse the pork bones and trotters under cold water, trimming any excessively bloody bits or loose cartilage. Pat dry.

Place bones in a large stockpot and cover with cold water. Bring to a rolling boil over high heat. Boil vigorously for 10 minutes to remove impurities and blood.

Drain bones in a colander and discard the blanching water. Rinse bones and the pot briefly to remove scum — this reduces cloudiness from surface impurities.

Preheat oven to 425°F (220°C). Spread blanched bones and trotters on a rimmed baking sheet, drizzle with 1 tbs neutral oil, and roast 25–35 minutes until well browned. Roasting adds depth but is optional if you prefer a lighter tonkatsu broth.

Transfer roasted bones to the stockpot. If you skipped roasting, simply place blanched bones into the pot.

Add 6 L (about 6 quarts) cold water to the pot with bones. Bring to a gentle simmer over medium-high heat. Avoid a hard rolling boil — maintain a low, steady simmer to extract collagen while keeping the broth relatively clear.

Skim any foam or scum from the surface with a fine mesh skimmer during the first 30–45 minutes of simmering as needed.

After the initial skim, add the aromatics: halved onion, leek, carrot, smashed garlic, sliced ginger, and dried shiitake mushrooms. Push them just below the surface so they infuse the liquid.

Lower heat to maintain a very gentle simmer. Cover partially with the lid offset to allow steam to escape. Simmer for 6–8 hours for a rich, collagen-rich broth; simmer up to 10–12 hours for a creamier, more concentrated texture. Check occasionally and top up with small amounts of hot water if liquid level drops below the bones.

During long simmering, continue to skim any fat or foam that accumulates. For an emulsified creamy texture (traditional tonkotsu style), you can occasionally increase heat to a low boil for 5–10 minutes and then return to simmer — this helps emulsify fat and marrow into the broth, creating a cloudy, milky appearance. Do this carefully to avoid over-reducing.

When the broth has developed a deep pork flavor and desired creaminess (after 6–12 hours), remove the pot from heat. Use tongs to discard large bones and strain the liquid through a fine-mesh sieve lined with cheesecloth into a clean pot or bowl to remove solids.

Skim off excess fat from the surface with a spoon or use a fat separator. If you prefer a silky mouthfeel, return the strained broth to gentle heat and whisk in 2 tbs unsalted butter until melted. Alternatively, reserve some fat for serving.

Season the broth gradually with 2 tsp kosher salt, 1 tbs light soy sauce, 1 tbs mirin, 1 tsp rice vinegar (optional), and 1 tsp white pepper. Taste and adjust: add more salt or soy for saltiness, mirin for a touch of sweetness, or a splash of vinegar to brighten.

Keep the broth hot for immediate use, or cool quickly and refrigerate. Refrigerated broth will firm up a layer of pork gelatin/fat — remove or stir back in when reheating depending on preference.

Use the Tonkatsu broth as the base for ramen: combine with prepared tare (soy/miso/salt) to create bowls, or use plain as a rich soup. Garnish with sliced chashu, green onions, soft-boiled eggs, bamboo shoots, and toasted sesame oil if desired.