Siraegi (dried radish greens)

Siraegi is not a separate plant but a preserved food: the leafy tops of the radish (mu), and sometimes outer napa cabbage leaves, dried for winter. Radish was a mainstay of the Korean kitchen and a famine food, and drying both the roots (mu-mallaengi) and the greens made it one of the most storable vegetables a household had.

Joseon writing records the method. Sallim gyeongje, an early-eighteenth-century household manual, advises storing large radishes pulled after the first frost in a pit to last until spring, and braiding the greens with straw rope to dry in the shade; before cooking, the dried leaves are soaked until they swell and then boiled. Siraegi was a winter namul above all. The writer Choe Yeong-nyeon, in Haedong jukji, listed it among the nine or more "old namul" eaten on Jeongwol Daeboreum, the first full moon of the lunar year, singling out the dark-green siraegi as especially wholesome. It still appears among the three- and five-color namul set out for ancestral rites and holidays, and on top of bibimbap.

Radish greens are usually dried in autumn, after the radish harvest, and eaten through the winter; today siraegi is also sold already boiled, and blanched siraegi can be frozen for long keeping.

In cooking, rehydrated siraegi is seasoned as namul, often with doenjang, soy sauce, garlic, chili powder and sesame oil (in North Gyeongsang it may be called siraegi doenjang-muchim); simmered in anchovy broth with doenjang and perilla seed for siraegi-guk, known in Gyeongsang dialect as sirak-guk; braised; and cooked with rice as siraegi-bap.

• Concentrated greens: Because it is dried, siraegi is dense in fiber, minerals and vitamin K by weight (Korean Food Composition Table); soaking and cooking dilute these considerably.
• Winter vegetable: Traditionally it supplied greens through months when little fresh produce was available.
• Vitamin K and warfarin: As a concentrated leafy green, siraegi is very high in vitamin K; people taking warfarin are advised to keep their intake of such foods consistent and to consult their doctor.
• Sodium caveat: Siraegi itself is low in sodium, but soups and namul seasoned with doenjang and soy sauce can be salty.