How to Make Korean Seaweed Soup

Seaweed soup gets better the longer it simmers

Seaweed soup is famous in Korea as the soup eaten on birthday mornings and after giving birth, but it is also an everyday soup. The ingredients are simple, yet a few steps clearly decide the flavor: soak the seaweed well and squeeze it dry, fry it with the beef in sesame oil for a nutty base, then add water and give it plenty of time. Rushed seaweed soup tastes thin, almost like plain water, while a long simmer draws savory flavor out of the seaweed and turns the broth cloudy and rich. That is also why many people say it tastes even better reheated.

Ingredients (example for three to four)

These are typical ranges. Dried seaweed swells a great deal when soaked, so start with what looks like slightly too little. Beef sold cut for soup is fine.

• A handful of dried seaweed (about 20 g)
• 150 to 200 g beef for soup, such as brisket or shank
• 1 to 2 tbsp sesame oil, 1 tsp minced garlic
• 1.5 to 1.8 L water
• 2 to 3 tbsp soup soy sauce, salt as needed
• Optional: a little fish sauce for extra savoriness

Method

The most important step is frying. Cooking the beef and seaweed together in sesame oil carries the nutty flavor into the broth and softens the seaweed's sea smell.

• Soak the dried seaweed in cold water for 20 to 30 minutes, then rub it firmly and rinse two or three times
• Squeeze out the water and cut it into easy-to-eat lengths
• Heat sesame oil in a pot and fry the beef over medium heat until the outside is cooked
• Add the seaweed and 1 tbsp soup soy sauce and fry for 3 to 5 minutes until the seaweed turns deep green
• Add the water, bring to a boil, then lower to medium-low and simmer for at least 20 to 30 minutes
• Add the garlic and adjust with soup soy sauce and salt

When the broth tastes fishy or flat

A fishy taste usually means the seaweed was not rinsed enough or went straight into water without frying. Rub and rinse soaked seaweed until little foam comes out, and fry it well in sesame oil. A flat broth most often just needs more time; turn the heat down and keep simmering and the flavor deepens. Adding a lot of soup soy sauce at the start makes the soup salty as it reduces, so use a little while frying and top up at the end after tasting. If the broth looks too dark, split the seasoning between soy sauce and salt.

Choosing and soaking seaweed

Dried seaweed comes in long, whole strands and in short pre-cut pieces. Whole strands are thicker, hold up to long simmering and keep a pleasant chew, which suits soup. Pre-cut seaweed softens quickly and is convenient, but turns limp if simmered too long. Either way, soak it in cold rather than lukewarm water so it does not go mushy. Soaking too long draws out much of the slippery coating and leaves it limp, so use the package time as a guide and lift it out once it feels soft. Leftover soaked seaweed can be squeezed dry and frozen for next time.

Variations

Swap the beef for clams or mussels for a lighter, briny version. Clean the clams first, add them with the water after frying the seaweed, and do not keep boiling once they open. Canned tuna makes a quick tuna seaweed soup, and without meat, anchovy or kelp broth keeps the soup from tasting hollow. Stir in two or three tablespoons of ground perilla seeds at the end for a nutty, thicker perilla seaweed soup. Some regions use chicken instead of beef.

Cooking it in Japan

The pre-cut dried seaweed common in Japanese supermarkets works fine. It is thinner than Korean soup seaweed and softens faster, so follow the short soaking time on the package and simmer a little less for a better texture. If you have no soup soy sauce, Japanese light-colored soy sauce is the closest match; regular soy sauce darkens the broth, so use less and finish with salt. A block of beef cut into cubes gives more flavor than thinly sliced meat.

Food safety and allergies

Seaweed is extremely high in iodine. People with a thyroid condition or under treatment, and anyone planning to eat large amounts daily during pregnancy or breastfeeding, should discuss intake with a doctor or other professional. Sesame in the oil, soy and wheat in soup soy sauce, and shellfish in the clam version are possible allergens. Cook beef through and discard any clams that do not open. Refrigerate leftovers once they cool and bring them back to a full boil before eating. Throw the soup away if it smells or tastes off.