Kombu is a dried kelp, rich in natural savoury flavour. A single sheet can flavour several litres of stock, which makes it one of the most useful Japanese pantry items.
Where to find it
Kombu is not stocked reliably by mainstream supermarkets. Larger stores sometimes carry it in the Japanese section, near nori and dashi ingredients. Smaller branches rarely do.
A Japanese grocer usually stocks a few grades and pack sizes. Online shops are the simplest option if you cannot find it nearby, and a dried pack keeps for a long time.
Kombu and nori
Kombu is thick, dried strips of kelp, used for stock and simmered dishes. Nori is thin, pressed seaweed sheets, used for wrapping sushi and snacks. The two are not interchangeable.
How to use it
Wipe the sheet with a damp cloth rather than washing it, since washing can wash away flavour. Add it to cold water and warm it gently. Remove it before the water boils to avoid bitterness. Use it for dashi, or add a strip to a pot of beans or simmered vegetables for depth.
Storage
Keep dried kombu in a sealed bag in a cool, dry cupboard.
Kombu is one half of the classic dashi pairing. For the bonito half, see our bonito flakes guide. For dashi bags, which save you the work, read our dashi bags guide. For a bowl of stock in use, try our everyday miso soup bowl.