Siraegi

Like other dark leafy greens, radish tops are a source of dietary fiber, calcium, and iron, and the leaves are generally richer in these than the white root itself. Drying concentrates them by weight, so a small handful of rehydrated siraegi adds meaningful fiber and minerals to a bowl of soup.

The greens of the radish are more nutrient-dense than the root most people picture as the vegetable.

The long soaking and boiling that siraegi needs also breaks down its tough plant fiber, which makes the greens easier to eat in quantity than they are fresh. As with most cooked vegetables, how much nourishment you actually get depends on keeping the cooking liquid, since some minerals leach into the broth.

For most of Korean history, winter meant a long stretch with little fresh produce. The autumn radish harvest, tied to kimjang (the communal making of winter kimchi), left heaps of leafy radish tops behind. Rather than throw them out, households bundled the greens and hung them from the eaves of the house to dry in the cold, dry wind.

By deep winter the bundles had gone dark and papery, ready to be soaked and cooked. Siraegi settled into the rhythm of frugal country cooking, a way to keep a vegetable on the table through the lean months between harvests.

Strings of radish greens drying under the eaves were once an ordinary sign, in rural Korea, that winter had arrived.

The food it belongs to is humble: temple kitchens, farmhouse tables, and the kind of soup a grandmother makes without a recipe. In recent decades siraegi has been reframed as a well-being food, prized for its fiber and rustic depth, and it now shows up in restaurants that once would have passed it over.

The classic use is siraegi-guk, a soup of rehydrated radish greens simmered with doenjang and anchovy or pork-bone stock until the greens are tender and the broth turns deep and savory. The greens carry that long-cooked flavor well.

Siraegi is happiest in a pot that simmers for a long time, where its sturdy texture becomes an asset.

Seasoned and tossed as a namul side dish with doenjang or soy sauce, sesame oil, and garlic, it makes a chewy, savory banchan. It is also stirred into rice as siraegi-bap, braised under oily fish such as mackerel, where it soaks up the fat, and added to restorative soups like haejangguk, the Korean pork-bone hangover soup, where it stands up to the rich broth.

Dried siraegi has to be brought back to life before cooking. Soak it in cool water for at least 30 minutes, longer for very dry, woody bundles, until the greens are pliable.

The stems are the part to watch: if tough strings or skins remain after soaking, peel or strip them so the cooked greens stay tender.

For tightly dried bundles, simmer in water until soft, then drain and rinse before seasoning or adding to soup. Squeeze out the excess water and cut into bite-length pieces. Keep dried siraegi in a cool, dry place or the freezer, where it lasts for months.