Ramen Tonkotsu Broth (Rolling-Boil Pork Bone Broth)

Name: Ramen Tonkotsu Broth (Rolling-Boil Pork Bone Broth)
Prep time: 1 h 7 min
Cook time: 6 h 28 min
Total time: 7 h 35 min
Yield: 6 servings
Cuisine: Japanese
Ingredients: 2 lb (900 g) pork trotters, split into 2–3 pieces each by the butcher; 3 lb (1400 g) pork neck bones, with some meat attached, rinsed; 1 head (about 10 cloves) (40 g) garlic, cloves separated and lightly smashed, skins removed; 3 oz (85 g) fresh ginger, unpeeled, scrubbed and cut into ¼-inch (6 mm) slices; 6 whole (90 g) scallions, roots trimmed, halved crosswise; 1 medium (200 g) yellow onion, peeled and halved through the root (optional); 8 cups (1900 ml) cold water, for soaking the bones (enough to fully cover; add more if needed); 18 cups (4250 ml) cold water, for blanching, enough to cover bones by 2 inches; 18 cups (4250 ml) cold water, fresh, for the main broth; 10 cups (2400 ml) boiling water, hot from a kettle, for topping up during the first 5 hours of boiling (about 1 cup / 240 ml per top-up, up to 10 top-ups; adjust to keep bones covered); 2 tsp (10 g) kosher salt, plus more to taste (amount for Morton; use 1 Tbsp for Diamond Crystal); ½ tsp (1 g) ground white pepper (optional)

From the MyKitchenBank Kitchen

A rich, milky, collagen-heavy pork broth made the traditional ramen-shop way: a hard rolling boil that breaks fat and gelatin into a creamy emulsion. Pork trotters give body and silkiness, neck bones give deep pork flavor, and garlic, ginger and scallions added for the final hour keep it fresh and aromatic.

Prep: 1 hr 7 min
Cook: 6 hr 28 min
Wait: 1 hr
Total: 8 hr 35 min
Makes: About 2.4 liters (10 cups) of broth, enough for 6 ramen bowls

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Ingredients

6 servings

2 lb (900 g) pork trotters, split into 2–3 pieces each by the butcher
3 lb (1400 g) pork neck bones, with some meat attached, rinsed
1 head (about 10 cloves) (40 g) garlic, cloves separated and lightly smashed, skins removed
3 oz (85 g) fresh ginger, unpeeled, scrubbed and cut into ¼-inch (6 mm) slices
6 whole (90 g) scallions, roots trimmed, halved crosswise
1 medium (200 g) yellow onion, peeled and halved through the root (optional)
8 cups (1900 ml) cold water, for soaking the bones (enough to fully cover; add more if needed)
18 cups (4250 ml) cold water, for blanching, enough to cover bones by 2 inches
18 cups (4250 ml) cold water, fresh, for the main broth
10 cups (2400 ml) boiling water, hot from a kettle, for topping up during the first 5 hours of boiling (about 1 cup / 240 ml per top-up, up to 10 top-ups; adjust to keep bones covered)
2 tsp (10 g) kosher salt, plus more to taste (amount for Morton; use 1 Tbsp for Diamond Crystal)
½ tsp (1 g) ground white pepper (optional)

Equipment (10)

12-quart (11 L) heavy stockpot with lid
Large bowl or second pot for soaking bones (at least 8 quart / 7.5 L)
Tongs
Fine-mesh skimmer or large spoon
Large fine-mesh sieve (or a regular sieve lined with cheesecloth)
Large heatproof container or second pot (at least 4 quart / 4 L) for the strained broth
Ladle
Immersion blender (optional)
Electric kettle or small pot for hot top-up water
Instant-read thermometer

Steps

Before you start

Plan for about 8½ hours start to finish. Most of it is unattended, but you need to be home to stir and top up the pot every 30–45 minutes.
Ask your butcher to split the trotters lengthwise or crosswise into 2–3 pieces; whole trotters release less collagen and will not fit well in the pot.
Clear space in your sink and have a large bowl or second pot ready for the soaking step.
Run your stove vent fan; a rolling boil of pork bones gives off a strong smell.
Before the main boil starts, boil about 3 liters of water in a kettle; you will use about 2.4 L of it in total to top up the pot, re-boiling the kettle as needed.

1
Soak the bones
- Place the trotter pieces and neck bones in a large bowl or second pot and cover with the cold soaking water (about 8 cups / 1.9 L, or enough to submerge them fully).
- Let stand at room temperature for 1 hour.
- Drain and discard the pinkish water.
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Ready when: Soaking water is cloudy pink
Tip: Do not skip the soak; blood left in the bones turns the broth gray and muddy.
2
Blanch the bones
- Put the drained bones in the 12-quart (11 L) stockpot and add the blanching water so the bones are covered by about 2 inches (5 cm).
- Bring to a full boil over high heat, about 12 minutes, then boil hard for 3 more minutes.
- Gray-brown scum will foam up and cling to the bones.
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Ready when: Thick gray scum covers the surface and the water looks murky
Tip: Never reuse this water; it holds the impurities you want gone.
3
Scrub bones and pot
- Carefully carry the pot to the sink and drain the bones into a colander, or lift them out with tongs.
- Rinse each bone under warm running water, rubbing off any dark clots, scum and loose bits; scrape out any dark residue along the neck bones with your thumb or a spoon.
- Wash the pot thoroughly to remove all scum, then return the clean bones to it.
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Ready when: Bones look pale pink-white with no dark specks and the pot has no residue
Tip: Use tongs and oven mitts; the bones and pot will be very hot.
4
Prep the aromatics
- Smash and peel the garlic cloves, slice the unpeeled ginger into ¼-inch (6 mm) rounds, halve the scallions crosswise and halve the onion through the root if using.
- Set aside in a bowl; they go in for the final hour only so they stay fresh and do not turn bitter.
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Tip: Start a kettle of water now so it is ready for the first top-up.
5
Start the rolling boil
- Add the 4.25 L (18 cups) fresh cold water to the pot with the clean bones so they are covered by about 2 inches (5 cm); the water level should sit at least 3 inches (8 cm) below the rim.
- Cover and bring to a boil over high heat, about 25 minutes.
- Remove the lid and skim off any foam that rises in the first few minutes.
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Ready when: Large bubbles break continuously across the entire surface
Tip: Starting with cold water extracts more collagen than adding bones to hot water.
6
Boil hard for 5 hours
- Lower the heat only slightly so the broth keeps a vigorous, constant rolling boil, and set the lid ajar by about 2 inches (5 cm) to limit evaporation.
- Expect to lose roughly 600–800 ml (2½–3½ cups) per hour.
- Every 30–45 minutes, stir well, scrape the bottom so nothing scorches, and add about 1 cup (240 ml) boiling water from the kettle, just enough to keep the bones covered.
- You will use about 2.4 L of top-up water over the 5 hours.
- The liquid turns from clear to cloudy to opaque off-white.
- At about 145°F (63°C) or higher the pork is already safe, and the bone meat reaches about 200°F (93°C) at a boil.
- Check by poking a trotter piece with a thermometer.
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Ready when: Broth is milky white, bone ends look soft and crumbly, trotter skin is very tender, and pork meat reads well above 145°F (63°C)
Tip: Always top up with boiling, not cold, water so the boil does not stop. Keep bones covered during these 5 hours so the broth does not darken.
7
Add aromatics, boil 1 more hour
- Add the garlic, ginger, scallions and onion (if using) and push them under the surface.
- Keep the vigorous rolling boil for 1 final hour with the lid ajar.
- Stir once or twice but do not add more water; the level will fall and the broth will reduce and thicken.
- Bones may peek above the surface now, which is fine; push them back under with tongs when you stir.
- The meat on the neck bones should fall away, and the broth should coat a spoon.
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Ready when: Broth is opaque creamy white, coats a spoon, and has reduced to about 2.4–2.8 L (10–12 cups) in the pot
Tip: One hour is enough for flavor; three or more hours of boiling would cook the aromatics out and make garlic and onion bitter or sulfurous. If much more than 3 L remains, boil uncovered a little longer; if under 2 L, stir in a splash of boiling water.
8
Strain the broth
- Turn off the heat.
- Use tongs to lift out the large bones and aromatics and discard them (or pick off the tender meat for another use).
- Set the sieve over the large heatproof container and ladle or pour the broth through.
- Press gently on the solids with the back of a ladle to extract all the liquid, but do not push through bone debris.
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Ready when: About 2.4 L (10 cups) of smooth, opaque broth, with no bone fragments
Tip: Strain while the broth is hot; once it cools it sets to a gel and is much harder to pour.
9
Emulsify and season
- For a creamier, silkier broth, blend the hot strained broth with an immersion blender for 20–30 seconds, keeping the blades submerged to avoid splatter.
- Stir in the kosher salt and white pepper (if using).
- Taste and add salt in ¼-teaspoon increments; the broth should taste pleasantly salty but still mild, as tare (seasoning) will be added in each bowl.
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Ready when: Broth is uniformly creamy and pale ivory with no oily separation
Tip: Skip the blender if you prefer a lighter broth; a good rolling boil will already have emulsified most of the fat.
10
Serve or cool
- To serve, reheat the broth to a gentle simmer (it should reach 165°F / 74°C) and ladle about 1 cup (240 ml) into each hot ramen bowl with tare, noodles and toppings.
- To store, cool the container in an ice bath, stirring, until lukewarm, then refrigerate.
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Ready when: Broth is steaming hot and just barely bubbling at the edges
Tip: Do not leave the broth at room temperature for more than 2 hours.

Good to know

Tips

Keep the boil vigorous the whole time. A gentle simmer produces a clear, thin broth, not tonkotsu.
Always top up with boiling water, never cold, and keep the bones covered during the first 5 hours; in the final hour let the broth reduce to reach the yield.
Evaporation varies with pot width and burner power. If your pot loses water faster, add more boiling water earlier; aim for about 2.4 L (10 cups) strained.
Season with salt only at the end, after the broth has reduced; salting early risks an over-salted result.

Make ahead

The broth can be made up to 4 days ahead. Cool it quickly in an ice bath, refrigerate in covered containers, and lift off or stir in the solidified fat as you like before reheating. It will set into a firm gel, which is a good sign of plenty of collagen.

Storage & reheating

Refrigerate in airtight containers for up to 4 days. Freeze for up to 3 months (leave 1 inch / 2.5 cm headspace). Do not store at room temperature longer than 2 hours. Thaw overnight in the fridge, then reheat in a pot over medium heat, stirring often, until steaming and bubbling gently at 165°F (74°C); add a splash of water if too thick.

Substitutions

pork trotters → pork femur or knuckle bones, or chicken feet. Pork femur bones add a similar richness; chicken feet (about 1 lb / 450 g) supply gelatin but make a slightly lighter, more chicken-leaning broth.
pork neck bones → pork back bones or pork spine. Use equal weight; expect slightly less meaty flavor.
yellow onion → leek (white and light green parts). Use 1 medium leek, halved lengthwise and rinsed, for a similar mild sweetness.
scallions → the green tops of 1 leek. Gives a similar fresh, green aroma.