Chueo-tang (Loach Soup with Perilla and Dried Greens)

Variations

• Namwon style (Jeolla): the loach is ground through completely so flesh and broth become one, with generous siraegi and perilla. The thickest version, now the most widespread, and the one this recipe follows.
• Seoul style (chu-tang): the loach goes in whole, simmered in a beef broth like yukgaejang, with fried tofu, tofu and mushrooms, and the soup stays clear and red. Nothing is ground, so it looks like a different dish entirely — closer to yukgaejang.
• Gyeongsang style: mostly outer cabbage leaves rather than radish greens, and a much heavier hand with the sansho pepper. Some households add Korean mint.
• Wonju style: more gochujang, so redder and hotter, and ground less finely so the flesh still has texture.
• Without whole loach: frozen ready-ground loach sold for this soup removes both the purge and the sieving. That is what most households actually do — skip steps 1, 2 and 4 and start at step 3.
• Thick soups in the same family: gamjatang builds the same body from siraegi and perilla, and cheonggukjang fills that role with fermented soybean instead. At the clear end of the scale sit seolleongtang and galbitang.

Tips

• Purging is half the broth. Loach live in mud, and unrinsed that mud goes straight into the soup. Coarse salt for 30 minutes, then rinse repeatedly until the foam stops. The salt coagulates the slime so it comes away; water alone does not do it.
• Sieve it twice. Once through a coarse sieve to hold back the big bones, then again through a fine one. One bone that gets through spoils the whole bowl's attention. Pour the cooking liquid through with it so the flesh passes easily.
• Do not throw the cooking water away. This soup has no separate stock: the water the loach simmered in is the broth, which is why the quantity (2.5L) is part of the recipe (stocks and broth).
• Loosen the doenjang before it goes in. Added as a lump it never disperses and stays a salty clot. Slacken it in a ladle of broth or push it through a sieve (fermented pastes).
• Ground perilla last. It is high in fat, so long boiling separates the oil out and leaves a chalky finish. It is a body-building ingredient — once it is in, one boil is enough (thickening sauces).
• Sansho at the table, by each person. This is structure, not preference. The numbing aroma of chopi is what cuts across the earthiness and the fishiness, and boiled in ahead of time that aroma is gone. People also differ enormously in how much of it they can take (blooming spices, balancing flavour).
• Peel the tough skin off the siraegi. It is dried radish tops, and the outside carries stringy fibre. Rubbing it off after boiling changes the texture completely (soaking).
• Season with doenjang; use salt only to finish. The saltiness has to arrive with savouriness or the broth falls flat. Seasoned with salt alone it is merely salty (salt and seasoning, building umami).
• Better the next day. The greens take up more broth and the body settles. But since perilla does not want more boiling, reheat gently over low heat (reviving leftovers).
• Freeze before the perilla. Portion the sieved broth and freeze it, and the soup is a short step away any time. Frozen after the perilla goes in, it separates on thawing (freezing and thawing).