Irish Kelp Dashi

The collective noun for kelp seaweed is actually “forest” and these great underwater forests, exposed only on the lowest tides, have species that grow so fast they increase their size by half a metre a day. Some of them measure a massive 80 metres deep.

Our Irish kelps are a little more restrained, but they too grow fast and thick in a forest of redy brown algae, half little tree, half large plant. We pick three of them, Oarweed, Forest Kelp and Sugar Kelp. They’re also known as Atlantic kombu.

Kombu has huge significance in cooking because it was the beginning of our love affair with the fifth basic taste: umami.

Umami was identified only in 1908, by Japanese scientist Kikunai Ikeda. He was a professor in the Tokyo Imperial University and he pinpointed the specific fifth taste which he found in the Japanese soup stock – kombu dashi.

This taste was more than simply sweet, sour, bitter or salty. Professor Ikeda named it umami, meaning “pleasant savoury taste”. This umami taste, first isolated in kombu is now said to be found in a range of foods from Parmesan cheese to tomato to roast chicken.

Scientifically we can now identify that this pleasant savoury taste comes from glutamate, and kombu, or kelp is rich in glutamate.

The Japanese, who are much further down the line than we are, when it comes to getting the best from seaweeds, use kombu in a liquid form. They simmer the seaweed in water, and this gives them something they call dashi. Dashi is the basic ingredient, or soup stock, on which the Japanese build their famous noodle recipes. It’s also the foundation of miso soup.

Irish kelp makes a wonderful dashi, and to make it you simply take a handful of kelp, make a few slits in the seaweed to help extract the glutamate and then simmer it gently in water. Ideally you should simmer it as close to 60ºC as you can manage. A Thermomix is great for this, otherwise use a temperature probe, or just keep on a very low simmer. Simmer the seaweed for an hour. This gives you an umami liquid, and also a delicious condiment. The seaweed becomes a leathery green. (The chlorophyll pigment in the plant is not soluble in water. That’s why you blanch greens like broccoli and spinach - to “set” the green, but that’s another story.)

Use the green seaweed cut into fine slices. Very healthy, and delicious in anything from scrambled egg to salad. Or add them to the noodles or soup you might make with your dashi.

The kombu dashi can be used as it is, or you can enhance the flavour further, turning up the umami taste and adding the other salty, sweet flavours that you get from dried bonito flakes, dried sardines, the liquid from soaked shiitake mushrooms. A simple miso soup can then be made using your dashi, heated, and then add some Japanese white miso stirred in off the heat, and garnish with the strips of seaweed, some cubed tofu and some sliced spring onion.

Note: When picking seaweed always use a knife or scissors. Only take the tip of the plant. Take one leaf from each plant and move on. You wouldn't pull plants up in mass from your garden, treat the shoreline like a garden that needs tending. Never take more than you need. Identify the seaweed before you cut it and know what you are looking for. We have a fabulous reserve of Irish seaweed, but it needs to be protected and cherished.