Umu-naengguk (우무냉국, Cold Agar Jelly Soup)

Ingredients

Equipment Needed

• •Sharp knife and cutting board
• •Large measuring jug or bowl for kelp water
• •Chilled stainless or glass serving bowls

Instructions

1. 1

   Steep the kelp

   Put the cold water and kelp in a measuring jug and refrigerate 30 minutes, or up to overnight. Lift out the kelp. Cold-steeping gives the broth a little body without making it taste cooked; boiling is for other soups, not this clear summer bowl.

   If you already keep chilled dashima water in the refrigerator, this becomes a 15-minute soup. That is a safe modern shortcut.
2. 2

   Cut the umu

   Rinse the agar jelly under cold running water and drain it well. Cut the block into 3 mm, or 1/8 inch, sheets, then stack a few sheets and cut them into long strips, 10 to 12 cm long. Do not cube it. Short pieces slide off the spoon; long strips catch the broth and make the dish what it is.

   Prepared umu sometimes carries the smell of its package water. Rinse it cold, but do not blanch it. Heat weakens the clean jelly texture you came for.
3. 3

   Salt the cucumber

   Toss the julienned cucumber with 1/4 teaspoon of the salt and set it aside for 5 minutes. Drain off any liquid, but do not squeeze it dry. The salt seasons the cucumber and pulls away water that would thin the broth.

4. 4

   Season the broth

   In a large bowl, whisk the cold kelp water with the vinegar, guk-ganjang, sugar, remaining 1/2 teaspoon salt, and grated garlic until the sugar dissolves. Taste it cold. It should be a little sharper and saltier than a soup you would drink alone, because the umu brings almost no flavor and the ice will soften the edges.

   If you only have regular soy sauce, use 2 teaspoons instead of 1 tablespoon, then add salt a pinch at a time. Darker soy sauce muddies the color and can cover the jelly.
5. 5

   Combine gently

   Add the umu strips and salted cucumber to the broth. Fold them through with chopsticks or clean fingers, lifting instead of stirring hard. Agar jelly breaks if you bully it, and broken bits make the bowl look tired before it reaches the table.

6. 6

   Serve icy

   Divide the soup among chilled bowls and add the cracked ice. Scatter scallion, green chili if using, and toasted sesame seeds over the top. Taste after the ice sits for 1 minute; if the broth has gone flat, add 1 teaspoon vinegar and a small pinch of salt to each bowl. Serve at once, while the vessel is beaded with cold.

Chef Tips

• •Buy prepared umu-muk from the refrigerated tofu and muk case. It should be pale, clean-smelling, and firm enough to lift without tearing. If it smells sour or crumbles in your hand, cook something else from the market today.
• •If you cannot find prepared umu, make a modern stand-in: whisk 2 teaspoons, about 6g, agar powder into 2 cups water, boil 2 minutes, pour into a shallow 8-inch dish, and chill until firm. The texture is firmer than seaweed-boiled umu, but it will carry the broth honestly.
• •The broth must taste sharper before the ice goes in. A flat umu-naengguk cannot be repaired with garnish. Fix it with vinegar, salt, and a little sugar, not more soy sauce.
• •Keep the jelly long. This is not fussiness. The long cut is what lets a nearly flavorless ingredient become satisfying in a cold soup.

Advance Preparation

• •The kelp water can be made up to 2 days ahead and kept refrigerated. Season it on the day you serve, especially if using raw garlic.
• •The umu can be cut 1 day ahead and stored submerged in cold water in the refrigerator. Drain it very well before adding it to the broth.
• •Do not assemble the soup far ahead. The ice dilutes the broth and the cucumber loses its clean edge, so combine everything just before the table is ready.

Frequently Asked Questions

Nutrition Information

1 serving (about 390g)