Gamja Guk (감자국): Clear Korean Potato Soup in 15 Minutes

Gamja guk (감자국) is a clear Korean potato soup simmered in anchovy-kelp broth, seasoned with Korean soup soy sauce (guk-ganjang) and a touch of fish sauce. Cubed waxy potatoes, onion and green onion cook in about fifteen minutes, no cream, no thickener, no roux. It’s the kind of soup my mom makes on tired weeknights and sick days in Seoul: light, deeply savory, and meant to be eaten with a bowl of rice and a few banchan on the side.

What is Gamja Guk?

Gamja-guk is a Korean potato soup. Because there is no cream involved, the broth remains clear and clean. It is typically seasoned with Korean soup soy sauce and salt. The secret to my specific recipe’s deep flavor is adding a touch of fish sauce. This traditional Korean comfort soup creates a rich broth even without many ingredients. It is non-stimulating, easy to digest, and a warming dish that truly comforts the body.

Ingredients for a Clear Korean Potato Broth

Ingredients

• 1 Large potato
• 1/2 Green onion
• 1/2 Small onion
• 1/2 tbsp Minced garlic
• 600ml Water
• 0.5 tbsp Korean soup soy sauce (Guk-ganjang)
• 0.5 tbsp Tuna sauce (Tuna fish sauce)
• 1 Korean Seafood stock coin
• 1–2 pinches Salt (adjust to taste at the end)

The Secret to Umami: Seafood Stock Coin & Tuna Sauce

• Korean Seafood Stock: If you are a beginner to Korean cuisine, Korean seafood stock coins and tuna sauce might be unfamiliar. In the past, Koreans had to buy dried anchovies and dried kelp separately to boil for broth. Nowadays, it is common to use a single stock coin that contains all those ingredients at once. It is easier to store and much more convenient for cooking. To achieve the taste of a traditional Korean potato soup, making a proper broth with anchovy or kelp is a must.
• Tuna Sauce: In Korea, we often add anchovy fish sauce to soups to boost umami. It adds a depth of flavor that regular soup soy sauce cannot provide alone. However, many Koreans are now using tuna sauce instead of anchovy sauce. While anchovy sauce can sometimes have a fishy aroma, tuna sauce lacks that fishy smell and provides an even deeper savory flavor. It is the key to this easy Korean soup recipe.

The Best Potatoes for Gamja Guk (And Why)

When making this Korean potato soup, you want potatoes that won’t break apart easily. I recommend using “waxy” potatoes like Yukon Gold or Red potatoes. Avoid starchy potatoes used for mashed potatoes (like Russets). You need a firmer potato that holds its shape to keep the broth clear and avoid a cloudy soup.

How to Make Gamja Guk: Step-by-Step

• Prepare the Vegetables: Peel the potato. Cut the potato and onion into bite-sized cubes.

• Prep the Aromatics: Thinly slice the green onion diagonally and mince the garlic.

• Boil the Base: Pour the water into a pot and add the seafood stock coin. Season the broth with the soup soy sauce and tuna sauce.

• Cook: Add the cubed potatoes, onions and minced garlic to the pot. Boil over medium-high heat for about 10 to 12 minutes, or until the potatoes are fully cooked and tender.

• Final Touch: Add the sliced green onion and boil for one more minute. Taste the soup, if it’s too bland, add 1 or 2 pinches of salt to suit your preference. This is the simplest way to enjoy potato soup without cream.

Troubleshooting: Cloudy Broth, Mushy Potatoes, Flat Flavor

My broth turned cloudy. What went wrong?

• Two things cloud gamja guk: boiling too hard, or skipping the rinse on your potatoes.
• Once you add the potatoes to the broth, keep the heat at a steady simmer, not a rolling boil. High heat agitates the starch out of the potatoes and turns your broth milky. It’ll still taste fine, but you lose that clean, clear look that makes this soup distinctly Korean.
• The other fix: after you cube your potatoes, rinse them under cold water for 30 seconds. This washes off the surface starch before it ever hits the pot.

The soup tastes flat. It’s not bad, just… bland.

Usually one of three things:

• Not enough guk-ganjang or salt. Korean soup soy sauce is saltier and more savory than regular soy sauce . Add it a little at a time or salt and taste as you go
• The anchovy stock wasn’t strong enough. If you’re using store-bought stock coins or powder, use a little more than the package says.
• You’re missing the fish sauce. The tuna sauce (or fish sauce) isn’t decorative. It adds a low, round umami note that guk-ganjang alone doesn’t give you.

My potatoes turned mushy before I even finished cooking.

• Use waxy potatoes: Yukon Gold, baby potatoes, or any variety that holds its shape when boiled.
• Cut your cubes on the larger side about 2–3 cm. Smaller pieces overcook in the 10–12 minute window this recipe needs.

What Koreans Eat with Gamja Guk (Banchan Pairings)

Gamja guk isn’t a standalone meal, it’s one part of a Korean table. The setup is always the same: a bowl of rice, a bowl of soup, and two or three banchan (반찬) arranged around them.

Here’s what actually goes on the table alongside gamja guk at home.

FAQ about Korea’s Potato Soup

Other Trendy Korean Potato Recipes to Try

• Gil-gamja: This is a potato snack that is currently surging in popularity in Korea. Unlike traditional fries, it is thinly crispy on the outside while remaining soft and stretchy on the inside. It is a trendy potato dish from the Gangwon province that people wait in line for two hours to eat.

• Cheese Potato Pancake: Shredded potatoes are pan-fried to maximize crispiness and filled with mozzarella cheese. Pairing this savory cheese potato “jeon” with Makgeolli (Korean rice wine) is the perfect way to melt away the fatigue of a long day.