Chashu Pork (Marinated Braised Pork Belly for Tonkotsu Ramen) Recipe

Braised in soy sauce, sake, and mirin, this tender pork belly is perfect for ramen.

Close up view of a slice of chashu pork in a bowl of ramen.

Serious Eats / J. Kenji Lopez-Alt

Why It Works

  • Rolling and tying the pork belly decreases its surface area, which helps the meat retain moisture during the long cooking time.
  • Leaving the rind on the pork belly insulates the meaty interior further and forms a pleasantly soft, gelatinous layer.
  • Braising the pork belly in a pan set in a 275°F (135°C) oven with the lid left slightly ajar keeps the braising liquid at 180-190°F (82-87°C), which ensures that the meat does not overcook.

We've talked about tonkotsu ramen broth and marinated soft-boiled eggs. Today is all about what is perhaps my favorite part of a bowl of ramen: the tender, salty, sweet, fatty, melt-in-your-mouth slices of braised pork belly known as chashu. It's a component of a perfect bowl of ramen that's all-too-often overlooked at restaurants. Dry, stringy, or chalky chashu tends to be the norm, but when a place really nails it, it can elevate a great bowl of ramen to a transcendent one. Transcendent is what we're after here.

Japanese chashu gets its name from the bright red Chinese barbecued pork known as char siu—you know, the stuff you see hanging in windows or stuffed into steamed bao?—and it probably came to Japan from China around the same time that ramen itself did. But like ramen, it's undergone some major alterations over the centuries. Unlike char siu, which is made by painting slices of pork shoulder with a thick, sweet marinade and roasting it, Japanese chashu is a simmered dish made with pork belly.

The question: What separates the bad chashu from the good, the good chashu from the great, and how do we recreate the best at home?

Basic Shaping

The first question is how to shape our pork belly before simmering it. Many home recipes for chashu are simplified and just cook the pork belly as a flat slab rather than rolling it. Indeed, many restaurants serve slabs of chashu instead or rolls. If you eat a lot of ramen, you've probably also noticed that rolled chashu is usually (but not always) moister and juicier than its more slabby counterpart.

A lean slab of pork belly sitting on a cutting board.

Serious Eats / J. Kenji López-Alt

This is no coincidence. See, when braising meats, there are a few different elements at play. Time and temperature are the most important, and we'll get to those in a moment, but surface area-to-volume ratio also plays a role. The more exposed surface a piece of meat has, the faster it cooks, and the more easily it loses moisture. And of course, the more moisture it loses, the dryer it becomes.

You might ask, "But doesn't cooking it in a moist environment keep it, well moist?" In fact, no. The amount of moisture a piece of meat loses almost entirely depends on the final temperature to which it's cooked to. With a flat slab of meat, there's simply more meat getting cooked to a higher temperature than in a rolled piece of meat.

With two identical pieces of pork belly, I found that cooking flat vs. rolled led to a good 18% more moisture loss. That's a significant difference!

What about rind on vs. off? It's up to you, but given enough cooking time, pork rind gets delightfully soft and gelatinous. It's also worth noting that skin is an insulator—that's one of its primary biological functions, after all—and it does an equally good job of it on a live pig as it does on a piece of rolled pork belly, making sure that the meat inside receives even, gentle heat.

TL/DR: Roll your rind-on pork belly. Secure with string. Good to go.

On Simmering

When simmering or braising meats, the goal is for your final product to be both moist and tender. Unfortunately, the cooking processes that lead to these ultimate goals are at odds with each other. See, the moistness of meat is dependent upon the final temperature it is cooked to. The hotter you cook it, the dryer it becomes. Take a look at this chart.

A chart where the X axis is the final internal temperature of the meat and the Y axis represents weight loss as a percentage of raw weight. The chart shows a relatively linear increase in weight loss as the temperature rises. At 160 degrees Fahrenheit, a roast has lost 30% of its initial weight. When cooked to 205 degrees, roughly 53% of the roast's initial weight has been lost.

Serious Eats / J. Kenji López-Alt

Moisture loss in meat is a nearly instantaneous process that's dependent on how much muscle fibers contract, which in turn is dependent on the temperature they are heated to. Heat a piece of meat up to 205°F (96°C), and moisture will get squeezed out like a tube of toothpaste. Just like a tube of toothpaste, that moisture is very very difficult to get back in once it's been squeezed out.

At the same time, tenderness is dependent upon cooking time. See, to turn tough cuts like pork belly tender, you have to break down connective tissue—mainly collagen—into softer molecules—mainly gelatin. This takes time.

The key is that the time it takes is also dependent upon cooking temperature. So keep your meat at 200°F (93°C), and it might take only a couple hours to reach tenderness. But of course, it'll also be hopelessly dry by then.

Chashu pork cooked sous vide.
Meat cooked in a sous-vide bag will be moister, but you've got to have a sous-vide cooker for this to work.

Serious Eats / J. Kenji López-Alt

Cook your meat at, say, 155°F (68°C), and you'll get extraordinarily moist meat, but it'll take up to 36 hours to tenderize. If you happen to have a sous-vide water cooker, this is, indeed, the best way to cook pork belly (see my post on deep-fried, sous-vide, 36-hour, all-belly porchetta for a discussion of the process). If you don't have one, your best bet is to use heat up your cooking liquid on the stovetop, but do the actual cooking in a low temperature oven, which provides a more even, gentler form of heat.

275°F (135°C) is about the lowest temperature my oven can reliably keep, which translates to an in-the-pot liquid temperature of between 180°F and 190°F (82-87°C) so long as the lid is kept ever-so-slightly ajar (this reduces vapor pressure on the liquid, letting it steam and cool down—liquid will stay about 10°F cooler in a cracked pot vs. a tightly lidded one). At this temperature, the pork takes about three and a half hours to get as tender as I like it.

Flavorings

Flavorings are pretty straightforward and classic. I use a mixture of soy sauce, mirin, sake, and sugar, with garlic, ginger, scallions, and a shallot or two thrown in. I heat it over the stovetop, add the pork, then finish it all in the oven.

What emerges a few hours later is this:

A fully braised log of chashu pork, standing on one end on a cutting board.

Serious Eats / J. Kenji López-Alt

Looks ridiculous, right? And it is. But wait! Don't try to cut into it straight away! Not only will you end up mangling your pork (if you cooked it right, it'll be soft enough to cut with a spoon and impossible to slice into even pieces), but you'll be robbing yourself of both moisture and flavor.

I know. The temptation to dig in right when it comes out of the oven is overwhelming. But good pork comes to those who wait. Let the pork cool down in its own cooking liquid in the fridge overnight and it'll not only come out more intensely flavored and moister, but chilled pork is also much easier to slice.

The Best Way to Reheat Chashu Pork

Only thing left to do is to warm up those slices before serving them in your ramen. There are a few approaches you can take.

Method 1: In the Soup

The lazy man's method, and a perfectly legitimate one. Just lay the slices in the hot soup just before serving, and in the time it takes to get the bowl from the kitchen to the table, it'll be hot, soft, and ready to eat.

Method 2: In the Cooking Liquid

An improved method which will add some great flavor to your slices. You may have noticed that after your pork is cooked, you end up with a ton of tasty liquid. You can, of course, use this liquid to marinate soft boiled eggs. It's also a tasty way to reheat your pork. Simmering the slices in the liquid for just a few seconds will heat them up and allow the liquid to soak into the inner surfaces, giving them more flavor all around.

Method 3: With a Torch

Slices of chashu pork being grazed with a propane torch. The slices have been placed on a foil-lined baking sheet.

Serious Eats / J. Kenji López-Alt

If you really want to go all-out, after simmering the slices, you can take a blowtorch to them (don't use those weak kitchen crème brûlée torches, go for an actual propane torch from a hardware store) to add charred flavor and crisp, crackly bits. This is the trick you pull out to seal the deal when that really cute Iron Chef fan finally agrees to let you cook them dinner.

Chashu slices that have been charred with a propane torch.

Serious Eats / J. Kenji López-Alt

Mmmmm... charred pork...

Now would you please excuse me while I go off in the corner to salivate in peace? Arigato.

The only question remaining is what to do with leftover chashu, and it's an easy one to answer: Make pork belly buns

March 2012

Recipe Facts

Prep: 10 mins
Cook: 3 hrs 5 mins
Active: 60 mins
Chilling Time: 12 hrs
Total: 15 hrs 15 mins
Serves: 6 to 8 servings

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Ingredients

  • 2-pound slab of boneless pork belly, skin-on

  • 1/2 cup soy sauce

  • 1 cup sake

  • 1 cup mirin

  • 1/2 cup sugar

  • 6 scallions, roughly chopped

  • 6 whole garlic cloves

  • One 2-inch knob ginger, roughly sliced

  • 1 whole shallot, split in half (skin on)

Directions

  1. Lay pork belly on cutting board and roll up lengthwise, with skin facing out.

    A rolled pork belly, ready to be tied with cut lengths of butcher twine.

    Serious Eats / J. Kenji López-Alt

  2. Using butchers twine, tightly secure pork belly at 3/4-inch intervals.

    The pork belly, rolled and tied into a cylinder.

    Serious Eats / J. Kenji López-Alt

  3. Preheat oven to 275°F (135°C). Heat 1 cup water, soy sauce, sake, mirin, sugar, scallions, garlic, ginger, and shallot in a medium saucepan over high heat until boiling. Add pork belly (it won't be submerged). Cover with a lid left slightly ajar. Transfer to oven and cook, turning pork occasionally, until pork is fully tender and a cake tester or thin knife inserted into its center meets little resistance, 3 to 4 hours. Transfer contents to a sealed container and refrigerate until completely cool.

    The tied pork belly in a pan with soy, mirin, and aromatics, ready to be braised.

    Serious Eats / J. Kenji López-Alt

  4. When ready to serve, remove pork belly and strain broth. Reserve broth for another use (like making ajitsuke tamago). Slice pork belly into thin rounds (it might help to cut it in half lengthwise first).

    Chashu pork being thinly sliced on a cutting board with a large slicing knife.

    Serious Eats / J. Kenji López-Alt

  5. Reheat pork belly slices in soup broth with noodles and other garnishes. Alternatively, heat a small amount of reserved broth in a skillet and heat pork slices in broth until hot or reheat with a blowtorch, charring its surface. Serve.

    Slices of chashu pork being reheated in a skillet with the braising liquid.

    Serious Eats / J. Kenji López-Alt

Special Equipment

Twine

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Nutrition Facts (per serving)
378 Calories
24g Fat
8g Carbs
27g Protein
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Nutrition Facts
Servings: 6 to 8
Amount per serving
Calories 378
% Daily Value*
Total Fat 24g 31%
Saturated Fat 9g 44%
Cholesterol 95mg 32%
Sodium 327mg 14%
Total Carbohydrate 8g 3%
Dietary Fiber 0g 1%
Total Sugars 7g
Protein 27g
Vitamin C 1mg 3%
Calcium 57mg 4%
Iron 1mg 7%
Potassium 314mg 7%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)