Authentic Tonkotsu Ramen Broth

Tonkotsu is the pork-bone ramen broth that looks almost like milk: opaque, creamy and rich enough to leave your lips slightly sticky. It gets that body from hours of hard boiling, which breaks down the collagen in pork trotters and bones and emulsifies it with the fat and marrow. Nothing is added to make it creamy.

To be honest about the time: a proper tonkotsu needs 10–12 hours of boiling, plus blanching and straining. The work itself is not difficult, but you need to be at home, topping up the pot every hour or so, and your kitchen will smell strongly of pork. If that isn’t practical, there’s a pressure-cooker version below that takes about 3 ½ hours.

A bowl of ramen is more than broth, so this page also covers the three other parts: the tare (the concentrated seasoning), an aroma oil, and the toppings. Makes about 2 litres (8 cups) of broth, enough for 6 bowls.

Where tonkotsu comes from

Tonkotsu ramen is usually traced to Kurume, in Fukuoka Prefecture on the island of Kyushu, in the late 1930s. The story that the cloudy broth began when a cook left a pot boiling too long is widely repeated, though hard to verify. It was the nearby city of Fukuoka, especially the Hakata district, that made it famous, with very thin, firm noodles and the custom of ordering a second portion of noodles, called kaedama, for the broth left in your bowl.

The broth

Ingredients

• 1.5 kg (3 ¼ lb) pork trotters, split lengthways or cut into pieces by the butcher
• 1.5 kg (3 ¼ lb) pork neck bones or femur bones, cut to expose the marrow
• About 5 litres (5 quarts) cold water, plus more for topping up
• 1 onion, halved, skin on
• 1 head garlic, halved crossways
• 5 cm (2 in) piece ginger, sliced
• Green parts of 4 spring onions (scallions)

Bones. Trotters give collagen, and that’s what makes the broth thick and lip-sticking. Neck and femur bones give meatier flavour and marrow. Ask a butcher to cut them, since a home cleaver won’t get through a femur. Asian butchers often sell bags of pork bones cheaply.

Pot. You need a heavy stockpot of at least 8 litres (8 quarts).

Method

1. Soak (optional). Cover the bones with cold water and refrigerate for 2–12 hours to draw out blood. This gives a cleaner-tasting broth.
2. Blanch. Put the bones in the pot, cover with cold water and bring to a boil. Boil for 10–15 minutes as grey scum rises. Drain into the sink.
3. Clean. Rinse each bone under running water, scrubbing off scum and dark clotted blood with a brush or chopstick, especially from the marrow ends. Scrape any hairs from the trotters. Wash the pot. This step is what keeps the finished broth from tasting muddy.
4. Boil hard. Return the bones to the clean pot, add 5 litres (5 quarts) fresh cold water and bring to a full rolling boil over high heat. Keep it at a vigorous boil, uncovered or with the lid ajar. A gentle simmer gives you a clear broth, which is good but is not tonkotsu.
5. Tend it. Every 45–60 minutes, top up with boiling water from a kettle to keep the bones covered, and stir, scraping the bottom. Trotters release so much gelatin that they can stick and scorch, and burned bits will spoil the flavour. Skim any foam in the first hour.
6. Watch it change. After 3–4 hours the broth turns cloudy. By 8 hours it should be opaque and pale beige. Keep going: the body keeps building even after the colour stops changing.
7. Add aromatics. For the last hour, add the onion, garlic, ginger and spring onion greens. Added earlier, they boil out and turn stale.
8. Finish and strain. After 10–12 hours in total, stop topping up and let the broth reduce to about 2 litres (8 cups). It’s ready when it’s milky and coats the back of a spoon. Strain through a fine sieve, pressing lightly. For an even creamier texture, blitz it with a stick blender for 30 seconds to re-emulsify the fat.

Don’t leave a pot at a rolling boil unattended or overnight. To split the work over two days, cool the pot quickly in a sink of iced water, refrigerate it, and bring it back to a full boil the next day.

Pressure-cooker tonkotsu

Use half the quantity of bones (1.5 kg / 3 ¼ lb in total) in a 6-litre (6-quart) pressure cooker. Blanch and scrub them as above, then add water up to the maximum fill line and no further; about half full is safest, since bone broth foams. Cook at high pressure for 2 hours and let the pressure release naturally, about 30 minutes. A sealed pot doesn’t churn, so the broth will be fatty but fairly thin. To fix that, boil it hard uncovered on the stove for 30–45 minutes with the aromatics, until it turns milky. The result is lighter than the long version, but makes a very good bowl.

The tare

Tare is the salty, concentrated seasoning that goes in the bowl first. The broth itself is left unsalted. Hakata shops often use a salt-based shio tare; a soy-based shoyu tare is easier at home.

• 120 ml (½ cup) Japanese soy sauce
• 60 ml (¼ cup) mirin
• 2 tbsp (30 ml) sake
• 5 × 5 cm (2 × 2 in) piece kombu
• 5 g (one small packet) katsuobushi (bonito flakes)

Soak the kombu in the soy sauce, mirin and sake for 30 minutes. Heat gently until just steaming, but don’t boil it, then remove the kombu. Take off the heat, add the katsuobushi, steep for 10 minutes and strain. It makes about 180 ml (¾ cup), enough for 6 bowls, and keeps for a month in the fridge.

Black garlic oil (mayu)

A spoonful of aroma oil on top adds a bitter, roasted note that cuts through the richness. Black garlic oil is the classic partner for Kumamoto-style tonkotsu.

• 60 ml (¼ cup) neutral oil
• 10 garlic cloves (about 40 g / 1 ½ oz), finely chopped
• 2 tbsp (30 ml) toasted sesame oil

Cook the garlic in the neutral oil over medium-low heat, stirring constantly, for 10–15 minutes. It goes golden, then brown, then black. Stop when it’s evenly black and smells deeply roasted rather than acrid. Off the heat, add the sesame oil, cool for a few minutes and blend until smooth. Use about 1 tsp per bowl. Keep it in the fridge and use within 4 days. For something milder, fry sliced garlic and spring onion in the oil just until golden.

Toppings

• Chashu: roll 750 g (1 ⅔ lb) skinless pork belly and tie it with string. Brown it all over, then simmer gently, covered, in 120 ml (½ cup) each soy sauce, sake and mirin, 50 g (¼ cup) sugar, 480 ml (2 cups) water, sliced ginger and spring onion, turning now and then, for 2–2 ½ hours, until a skewer slides in easily. Cool in the liquid and chill overnight so it slices neatly. Slice and sear or blowtorch just before serving.
• Ajitama (marinated eggs): lower 6 cold eggs into boiling water and cook for 6 ½–7 minutes for jammy yolks, then chill in iced water and peel. Marinate in 240 ml (1 cup) of the strained chashu liquid, diluted with 120 ml (½ cup) water, for 6–24 hours.
• Also traditional: thinly sliced spring onions, strips of rehydrated wood ear mushroom (kikurage), red pickled ginger (beni shoga), toasted sesame seeds, nori, and bean sprouts.

Assembling a bowl

1. Bring the broth to a full boil. It must be very hot, as it cools the moment it hits the bowl.
2. Warm each bowl with boiling water, then tip it out.
3. Put 2 tbsp (30 ml) tare and 1 tsp black garlic oil in the bowl. Ladle in 330 ml (1 ⅓ cups) broth and stir.
4. Cook 120 g (4 oz) fresh or 90 g (3 oz) dried thin, straight ramen noodles per bowl, following the packet but erring firm. Hakata noodles take as little as 1 minute. Drain well, shaking off as much water as you can.
5. Add the noodles, fold them once, and top with sliced chashu, a halved egg and your other toppings. Eat right away.

Common mistakes

• Simmering instead of boiling. The most common reason home tonkotsu comes out clear and thin.
• Skipping the blanch and scrub. It leaves the broth grey and tasting of blood.
• Letting it catch. Stir and scrape the bottom every time you top up.
• Salting the broth. Seasoning goes in through the tare, bowl by bowl.
• Wet noodles. Water dripping from the noodles dilutes the broth.

Storage

Cool the broth fast, in a sink of iced water or in shallow containers, and refrigerate within 2 hours. It sets to a firm jelly, which is a good sign. It keeps for 4 days in the fridge or 3 months in the freezer, frozen in 330 ml portions. Bring it to a full boil and whisk or blend to re-emulsify before serving. Chashu keeps for 5 days in the fridge, and eggs for 3 days once marinated.

If the tare has you reaching for Japanese flavours, our air-fryer honey miso salmon bites are a much faster weeknight dinner. And for another soup built on long, patient cooking, try our classic French onion soup.

For more on cooling, freezing and reheating, see our make-ahead, storage and freezing guide.

Tonkotsu Ramen Broth (with Tare, Black Garlic Oil and Toppings)

Pork trotters and bones blanched, scrubbed and boiled hard for 10–12 hours into a milky, collagen-rich broth, served with shoyu tare, black garlic oil, chashu pork belly, marinated eggs and thin ramen noodles.

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Prep Time 1 hour hr

Cook Time 12 hours hrs

Total Time 13 hours hrs

Course Main Course, Soup

Cuisine Japanese

Servings 6 bowls (about 2 litres / 8 cups broth)

Ingredients

  

Broth

• 1.5 kg (3 ¼ lb) pork trotters, split or cut into pieces
• 1.5 kg (3 ¼ lb) pork neck bones or femur bones, cut to expose the marrow
• about 5 litres (5 quarts) cold water, plus boiling water for topping up
• 1 onion, halved, skin on
• 1 head garlic, halved crossways
• 5 cm (2 in) piece ginger, sliced
• green parts of 4 spring onions (scallions)

Shoyu tare

• 120 ml (½ cup) Japanese soy sauce
• 60 ml (¼ cup) mirin
• 2 tbsp (30 ml) sake
• 1 piece kombu 5 × 5 cm / 2 × 2 in
• 5 g (one small packet) katsuobushi (bonito flakes)

Black garlic oil (mayu)

• 60 ml (¼ cup) neutral oil
• 10 garlic cloves (about 40 g / 1 ½ oz), finely chopped
• 2 tbsp (30 ml) toasted sesame oil

Chashu and marinated eggs

• 750 g (1 ⅔ lb) skinless pork belly, rolled and tied
• 120 ml (½ cup) soy sauce
• 120 ml (½ cup) sake
• 120 ml (½ cup) mirin
• 50 g (¼ cup) sugar
• 480 ml (2 cups) water
• 3 slices ginger and 2 spring onions
• 6 large eggs

To serve

• 720 g (1 lb 10 oz) fresh or 540 g (1 lb 3 oz) dried thin, straight ramen noodles (120 g / 90 g per bowl)
• thinly sliced spring onions, rehydrated wood ear mushroom strips, beni shoga (red pickled ginger), toasted sesame seeds, nori

Instructions

 

• Optional: soak the bones in cold water in the fridge for 2–12 hours.
• Cover the bones with cold water, bring to a boil and boil 10–15 minutes. Drain, scrub each bone clean of scum and clotted blood under running water, and wash the pot.
• Return the bones to the pot with 5 litres (5 quarts) cold water. Bring to a full rolling boil and keep it boiling hard, uncovered or lid ajar.
• Every 45–60 minutes, top up with boiling water to keep the bones covered and stir, scraping the bottom so nothing scorches. Skim foam in the first hour.
• Meanwhile, make the chashu: brown the tied belly all over, then simmer covered in the soy sauce, sake, mirin, sugar, water, ginger and spring onions for 2–2 ½ hours, turning occasionally, until a skewer slides in easily. Cool in the liquid and chill overnight.
• Make the eggs: boil fridge-cold eggs 6 ½–7 minutes, chill in iced water, peel, and marinate 6–24 hours in 240 ml (1 cup) strained chashu liquid mixed with 120 ml (½ cup) water.
• Make the tare: soak the kombu in the soy sauce, mirin and sake for 30 minutes, heat until steaming without boiling, remove the kombu, add the katsuobushi off the heat, steep 10 minutes and strain.
• Make the black garlic oil: cook the garlic in the neutral oil over medium-low heat, stirring constantly, 10–15 minutes until evenly black. Off the heat add the sesame oil, cool slightly and blend smooth.
• Add the broth aromatics for the last hour. After 10–12 hours in total, let the broth reduce to about 2 litres (8 cups), until milky and spoon-coating. Strain through a fine sieve; blend 30 seconds with a stick blender if you like.
• To serve, bring the broth to a full boil. In each warmed bowl put 2 tbsp (30 ml) tare and 1 tsp black garlic oil, add 330 ml (1 ⅓ cups) broth and stir. Add well-drained, firm-cooked noodles and top with seared chashu slices, a halved egg and the other toppings.

Notes

• The broth must boil hard, not simmer, to turn milky. Never leave it boiling unattended or overnight; to split over two days, cool quickly in iced water, refrigerate, and return to a full boil the next day.
• Pressure cooker: 1.5 kg (3 ¼ lb) blanched, scrubbed bones in a 6-litre (6-quart) cooker, filled no more than about half full. High pressure 2 hours, natural release, then boil hard uncovered with the aromatics for 30–45 minutes until milky. About 3 ½ hours in total.
• Storage: broth 4 days in the fridge or 3 months frozen; tare 1 month refrigerated; black garlic oil 4 days refrigerated; chashu 5 days; marinated eggs 3 days.
• Do not salt the broth; season each bowl with tare.

Keyword ajitama, black garlic oil, chashu, Hakata ramen, mayu, pork bone broth, pressure cooker ramen, ramen broth from scratch, shoyu tare, tonkotsu broth, tonkotsu ramen

Photo: Diana Nguyen on Pexels