As some of you already know, Kombu is one kind of seaweed that is known as containing umami. We use it to make dashi, mostly in the Kansai area.
So what is Kombu? It is often translated to "Kelp". Kombu is one type of kelp but it is not giant kelp which is more commonly found in Europe. Kombu that is used in Japanese cooking is species kelp that is found in the sea around Hokkaido area. (North of Japan), so kombu is different from giant kelp.
Types of Kombu
Ma kombu - Is known as high grade. Slightly sweet. Dashi colour is clear.
Rausu kombu - Quite soft. The dashi that is made from this kombu is rich, slightly yellow. This kombu is used for kombu tea as well.
Rishiri kombu - Tastes quite salty, dashi is clear. Often used in Kyo-Ryori (Kyoto cuisine).
Hidaka kombu - Soft and easy to extract the flavour in boiling water, so this kombu is actually used as food ingredients. Often used in Kanto (Tokyo) area. Used in Oden.
Atsuba kombu- Often covered with white powder that contains umami. Really thick and used in sushi.
Naga kombu - This kombu is quite thin compared to others. Used in Okinawan cuisine.
Hosome kombu - Is really thin and bit sticky. Used as topping.
White Powder On Kombu
If you've ever seen or bought kombu and it's had a white powder coating it, it's easy to think that it's bad quality, dirty or sea salt, however, it isn't. So what is it? It's actually glutamic umami called Mannit. They are nutrients derived from kombu and have no harm to the body. When kombu starts to dry out, water evaporates but umami doesn't, and it stays as white powder on kombu. If you mind about white powder, wipe lightly with a kitchen towel.
How to Make Kombu Dashi?
We sell some powdered and soup type kombu dashi, but you can try authentic Japanese way to make dashi! (From Kombu net Komb.or.jp)
1 All you need is: 1L of water and 10-20g of kombu
2 wipe the surface of kombu lightly to remove white powder if it's too much on it.
3 Soak kombu in the water for about 30min
4 After that, heat the water and before it starts boiling, remove kombu.
After you've made your dashi, you're left with hydrated kombu, which is often disposed of, but can you eat it? Of course, you can! We can cook something with it after taking dashi!
Cut kombu to smaller pieces, add mirin and sprinkle some sesame on them. Heat them in a microwave until kombu becomes crispy. To add more flavour, add salt before you eat.