Korean Radish Soup (Mu Guk): Clear, Savory, and Simple

Korean radish soup, or mu guk, is a clear Korean soup of tender Korean radish in a savory broth, often made with anchovies and kelp. This version keeps the broth light and gently sweet, with garlic, scallions, and Korean soup soy sauce providing a clean, satisfying finish.

Ingredients

7 cups (1.65 L) cold water
4-inch (10 cm) piece dried kombu, about 5 g
8 large dried anchovies, about 12 g, heads and guts removed
1 lb (450 g) Korean radish, peeled and cut into thin bite-size pieces
2 garlic cloves (6 g), finely chopped
1 tablespoon (15 ml) Korean soup soy sauce (guk ganjang)
1 teaspoon (5 ml) fish sauce, optional
1 teaspoon (5 ml) toasted sesame oil
2 scallions (about 30 g), thinly sliced
¼ teaspoon (1 g) fine salt, plus more to taste
⅛ teaspoon (0.5 g) ground black pepper, plus more to taste

Instructions

Prepare the ingredients. Peel the radish and cut it into thin slices or short pieces about ¼ inch (6 mm) thick. Keeping the pieces close in size helps them soften evenly without turning mushy. Chop the garlic and slice the scallions, separating a small handful of the green tops for serving if you like. If the anchovies are not already cleaned, remove their heads and split them to take out the dark inner guts; this helps keep the stock from tasting bitter.
Start the kombu stock. Put the cold water and kombu in a medium pot. Set it over medium heat and warm it for about 5 minutes, stopping just before the water boils; small bubbles may gather around the edge. Turn off the heat and let the kombu steep for 10 minutes. Remove it with tongs before adding the anchovies. Avoid boiling kombu hard, since prolonged boiling can make its broth cloudy or give it a slippery texture.
Simmer and strain the anchovy broth. Add the cleaned dried anchovies to the pot and bring the liquid to a gentle simmer over medium heat, about 3–5 minutes. Lower the heat and simmer for 10 minutes, skimming away any foam that gathers on top. Strain the stock through a fine-mesh sieve into a clean bowl or another pot, then discard the anchovies. You should have a pale, savory broth; a little loss to evaporation and straining is normal.
Cook the radish. Return the strained broth to the pot and add the radish and chopped garlic. Bring it back to a gentle simmer, then cook uncovered for 10–12 minutes. The radish is ready when a chopstick or the tip of a knife slides into a piece easily, but the pieces still hold their shape. Start checking at 10 minutes because thinly cut radish softens quickly; thicker pieces may need a few more minutes.
Season and finish. Stir in the soup soy sauce, optional fish sauce, sesame oil, salt, and pepper. Simmer for 2 minutes, then taste a spoonful of broth before adding any more salt. Stir in most of the sliced scallions and turn off the heat. Let the soup sit for 1 minute so the flavors settle, then serve hot with the remaining scallions scattered over each bowl.

Tips

Use Korean radish when you can. Korean radish, or mu, is usually short and stout with a green shoulder and crisp white flesh. Daikon is a practical substitute and cooks in much the same way, though it can taste a little milder and have a less dense texture. Peel either kind and cut it evenly so each piece finishes at the same time.
Keep the stock gentle. A hard boil can cloud the broth, while overcooked anchovies or kombu can leave a bitter or overly strong taste. Take the kombu out after its steep and strain the anchovies after their short simmer. A clear soup does not need to be perfectly transparent; the main goal is a clean, mellow flavor.
Season gradually. Soup soy sauce and fish sauce vary in saltiness, and the broth reduces slightly as it cooks. Add the measured amounts first, then taste before adding more. If the soup tastes flat rather than distinctly salty, a small extra splash of soup soy sauce can add savory depth; if it is too salty, dilute it with a little hot water.
Do not cook the radish until it collapses. Begin checking at 10 minutes and stop once the center is tender. The radish will continue softening slightly in the hot broth after the pot comes off the heat. If you plan to serve leftovers later, keeping the pieces just tender in the first cooking helps them retain more shape when reheated.

Serving Suggestions

Serve mu guk in small bowls alongside a Korean-style meal, or make it the center of a simple lunch with a bowl of steamed short-grain rice. The mild broth pairs well with banchan such as kimchi, seasoned spinach, bean sprouts, or crisp pickled vegetables. Those sides add contrasting heat, acidity, and texture without needing to change the soup itself.

For a more filling meal, serve a larger portion with rice and a plate of pan-fried tofu, grilled mushrooms, or a savory vegetable pancake. Set out extra sliced scallions, black pepper, and a small dish of kimchi so each person can adjust their bowl. The soup is best served hot, while the radish is tender and the broth still tastes light and fragrant.

Variations

Beef mu guk: For a common beef variation, use about 6 ounces (170 g) thinly sliced beef brisket or another tender beef cut. Brown it in 1 teaspoon (5 ml) neutral oil in the soup pot, then add the radish and garlic and cook briefly before adding prepared anchovy-kelp stock. Simmer until the radish is tender. Check the thickest piece of beef with a food thermometer: USDA FSIS lists 145°F (63°C) with a 3-minute rest as the safe minimum for whole cuts of beef. Rest the checked piece for 3 minutes before returning it to the soup. Beef versions are often seasoned with soup soy sauce and can be finished with sesame oil.

Make it vegetarian: Omit the dried anchovies and fish sauce. For a fuller plant-based stock, simmer a few dried shiitake mushrooms with the kombu, then strain the stock and slice the mushrooms to return to the soup. The result has a deeper mushroom flavor and will not taste exactly like the anchovy version, but it works well with the radish and garlic. Check that your soup soy sauce is suitable for your dietary needs.

Make it a little spicier: Add a small pinch of Korean red pepper flakes (gochugaru) with the garlic, or serve the flakes at the table. Use a light hand if you want to preserve the soup’s clear, gentle character. A few drops of toasted sesame oil at the end can also make the aroma more pronounced, but too much will cover the delicate broth.

Storage and Reheating

Cool the soup promptly and refrigerate it within 2 hours of cooking, in a covered container. It keeps for 3–4 days in the refrigerator. The radish will soften as it sits, so the broth may taste a little sweeter and the pieces may be less firm on the second day; that is normal. For easier reheating, store rice separately rather than leaving it in the soup.

Reheat only the portion you plan to eat in a saucepan over medium heat, stirring occasionally until it is steaming hot throughout. If the broth has reduced or tastes more concentrated, add a splash of water and adjust the seasoning after warming. For leftovers, USDA FSIS recommends reheating to 165°F (74°C); check the center with a food thermometer. You can freeze the soup for up to 2 months in a freezer-safe container, though the radish may become softer after thawing. Thaw it in the refrigerator and reheat thoroughly; do not leave it at room temperature to thaw.

Frequently Asked Questions

What is Korean radish soup called?
It is commonly called mu guk, with mu meaning Korean radish and guk meaning soup. Recipes vary by household and region: some use beef, while others build a light broth from dried anchovies and kelp. This recipe uses the anchovy-kelp style, so it has a clear broth without meat.

Can I use daikon instead of Korean radish?
Yes. Peel the daikon and cut it into pieces of similar thickness to the Korean radish in the recipe. Its flavor is usually milder, so taste the broth near the end and adjust the soup soy sauce, salt, or fish sauce as needed. Cooking time is similar, but check tenderness rather than relying only on the clock.

What can I use instead of Korean soup soy sauce?
Use regular soy sauce in a smaller amount to start, then add salt gradually. Regular soy sauce is darker and often sweeter, so it changes the color and flavor of the broth; the soup may look less clear and taste less cleanly savory. Fish sauce can add some savory depth, but it is not a direct replacement for soup soy sauce.

Why does my anchovy broth taste bitter?
The anchovies may have been simmered too long, or their dark inner guts may not have been removed. Clean the anchovies, keep the broth at a gentle simmer, and strain them after 10 minutes. Kombu can also become unpleasantly strong if boiled hard or left in the pot for an extended time, so remove it after the 10-minute steep.

Can I make mu guk ahead?
Yes. Make the soup a day ahead, cool it promptly, and refrigerate it covered. The flavors will meld, although the radish will soften further. Reheat it gently and check the seasoning before serving; add a little water if the broth has become too concentrated. Keep cooked rice and fresh garnishes separate until serving.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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