Kimchi is Korea's national dish: vegetables — most classically napa cabbage, but also daikon radish, cucumber and more — salted, then layered with a paste of gochugaru chilli flakes, garlic, ginger, scallion and usually a salted seafood element, and left to ferment. Lactic-acid bacteria make it sour, spicy, funky, deeply umami and lightly fizzy, and it is eaten cold as banchan and cooked into stews and fried rice.