Making Yuksu: Anchovy-Kelp Stock

Yuksu means stock or broth. Korean cooks make it from beef, bones, shellfish or vegetables, but the everyday workhorse is myeolchi-dashima yuksu: dried anchovies simmered with dried kelp. It takes under half an hour and gives soups, stews, noodle broths and braises a clean, savory backbone.

The ingredients

• Dried anchovies (myeolchi). Anchovies are boiled and dried soon after they are caught, and the Encyclopedia of Korean Culture notes that boiled-and-dried anchovy is one of the main ways the fish is eaten in Korea. For stock, cooks use medium to large anchovies; tiny ones are reserved for stir-fries such as myeolchi-bokkeum.
• Dried kelp (dashima). Thick, dark sheets of kelp. Wipe off any grit with a damp cloth rather than rinsing; the white bloom on the surface is natural and part of the flavor.
• Optional additions. Korean radish, onion, the white parts of green onion, garlic, dried shiitake mushrooms or dried shrimp all deepen the stock.

Step by step

1. Prepare the anchovies. For larger anchovies, pull off the head if you like and split the body to remove the dark gut, which can make the stock bitter. Small and medium anchovies are often used whole. Some cooks toast the anchovies briefly in a dry pot to reduce fishiness.
2. Start cold. Put anchovies and kelp in cold water (a typical home ratio is about 10–12 anchovies and one or two palm-size pieces of kelp for 1.5–2 liters of water). A 20- to 30-minute soak gives the kelp a head start.
3. Bring up to a boil, uncovered. Leaving the lid off lets fishy aromas escape.
4. Remove the kelp early. Take the kelp out when the water comes to a boil or within about 10 minutes. Boiled too long, kelp releases a slippery, viscous substance that clouds the stock and can add bitterness.
5. Simmer the anchovies. Continue at a gentle boil for about 10–15 minutes. Longer cooking does not add much and can make the stock taste harsh.
6. Strain. Pour through a fine sieve and discard the solids.

Why anchovy and kelp work together

The pairing is a textbook example of umami synergy. Kelp is rich in free glutamate, the amino acid behind savory taste. Dried small fish such as anchovy are rich in inosinate, a nucleotide that, according to the Umami Information Center, can reach several hundred milligrams per 100 grams in boiled-and-dried fish. When glutamate and inosinate are tasted together, perceived savoriness is far stronger than either alone. Japanese dashi relies on the same principle with kelp and bonito flakes; Korean anchovy-kelp stock is a close cousin made with a different fish.

How it is used

• Soups and stews. The Encyclopedia of Korean Culture notes that anchovy broth suits doenjang-based soups particularly well, while beef stock is the classic base for clear soups.
• Braises. Using stock in place of water adds depth to jorim such as dubu-jorim and gamja-jorim; see braising.
• Noodles and savory custards. Anchovy stock is a common base for warm noodle soups and for steamed egg, gyeran-jjim.

History

Anchovies have long been fished off the Korean coast. The encyclopedia cites the early-19th-century natural history Jasan Eobo (1814), which describes fishermen using lights at night to attract schools, and notes that anchovy grew into a major commercial fishery in the late 19th century. Dried anchovy became an everyday ingredient on the Korean table, both as a banchan and as the foundation for stock.

Storage and tips

• Cool the stock quickly and refrigerate it in a covered container for a few days, or freeze it in portions.
• The stock is unsalted; season the finished dish rather than the stock, ideally with soup soy sauce (guk-ganjang). See making jang.