Jaecheop-guk (Marsh Clam Soup)

Ingredients

Equipment Needed

• •Large bowl or basin, at least 3 quarts, for purging
• •4-quart heavy pot
• •Slotted spoon
• •Fine-mesh strainer lined with damp cotton cloth or a coffee filter

Instructions

1. 1

   Sort and purge

   Pick through the clams and discard any with cracked shells, and any open clam that does not close when tapped. Dissolve the coarse sea salt in 2 liters cold water in a large bowl, then add the clams. The water should cover them by about 2 cm. Cover the bowl and keep it in a cool, dark place for 2 hours so the clams spit out sand. This is the step people shorten, and then they blame the river for their own impatience.

   This is a light brine, not seawater. Jaecheop are river clams, and too much salt shocks them closed instead of helping them purge.
2. 2

   Rinse hard

   Lift the clams out of the bowl with your hands or a sieve, leaving the grit behind. Do not pour the purge water over them. Rinse under cold running water, rubbing the shells between your palms until the water runs clear and the shells feel clean. Trim the buchu now and cut it into 2-inch lengths, because the end of this soup moves quickly.

   If your fishmonger sold the clams already purged, still sort them and give them a 30-minute soak in cool water. Trust the fishmonger, but check the bowl.
3. 3

   Start cold

   Put the rinsed clams and 7 cups cold water in a 4-quart pot. Set it over medium heat and bring it slowly to a gentle boil, 8 to 10 minutes. Starting from cold water draws flavor from the tiny clams before their meat tightens. High heat opens the shells fast, but it gives you a thinner broth.

4. 4

   Skim and stop

   As the shells open, skim off the gray froth that gathers on top. Once most of the clams have opened, boil only 2 minutes more, then turn off the heat. Scoop the clams out with a slotted spoon. Discard any clams that remain closed. Overboiling makes the meat tough and clouds the clean broth you worked for.

5. 5

   Strain the broth

   Line a fine-mesh strainer with damp cotton cloth or a coffee filter and strain the broth into a clean pot, leaving the last spoonful of grit behind if you see any. When the clams are cool enough to handle, pick the meat from the shells. This is small work. Do it anyway. One gritty shell at the table ruins more than the cook's mood.

6. 6

   Season with restraint

   Return the strained broth and picked clam meat to the pot and warm it over medium heat. Add 1 teaspoon fine sea salt, stir, and taste. Add up to 1/4 teaspoon more only if the broth tastes thin or unfinished. Do not add soup soy sauce here; it darkens the soup and covers the clams. The broth should taste clean, lightly mineral, and gently salty, not like seawater.

   Salt after straining. Grit and froth trick the tongue, and you will over-season before the broth is clean.
7. 7

   Add chives last

   Turn off the heat and scatter in the 60g buchu. Fold once, just until the chives turn bright green and bend. Ladle into bowls at once and serve with cooked white rice and kimchi. The soup is pale on purpose. Let it taste like itself.

Chef Tips

• •Buy live clams from a trusted market. The shells should be closed or close when tapped, and they should smell clean, like water and shell, not sour or muddy. Do not gather river clams yourself unless the water is monitored for shellfish harvest.
• •Safe shortcut: ask the fishmonger for purged jaecheop. Unsafe shortcut: skipping the cloth-lined strainer. Tiny clams carry tiny sand, and a fine sieve alone does not always catch it.
• •Buchu is not the same as scallion. Korean garlic chives give a green, allium edge without sweetening the soup. If you cannot find buchu, use Chinese garlic chives; if you use scallion, use only one thinly sliced stalk and know the dish has changed.
• •Frozen shelled jaecheop can make a weeknight version. Use 350g thawed clam meat with any package liquid and 5 cups water, simmer 5 minutes, strain, then return the meat. It will be thinner than live-clam broth, but it is honest when the market is not kind.
• •Do not strengthen weak clams with anchovy broth. Then you are making anchovy soup with clams in it. If the clams are poor, cook kongnamul-guk or muguk tonight and wait for better shellfish.

Advance Preparation

• •Purge the clams 2 to 4 hours before cooking and keep them cool. Do not leave live clams submerged overnight; they need oxygen, and tired shellfish make poor soup.
• •If you need to work ahead, cook through the strained broth and picked clam meat, then refrigerate them together up to 1 day. Reheat to a full simmer and add the buchu only at the end.
• •Live clams are best cooked the day you buy them. If you must hold them, keep them in a colander set over a bowl, covered with a damp towel in the refrigerator, and cook within 24 hours.

Frequently Asked Questions

Nutrition Information

1 serving (about 625g)