Tucking into Hélène Darroze’s poached sea bass with kombu, creamy marinière of shellfish, girolles and spinach at the Connaught in Mayfair, it struck me that kombu (Japanese dried kelp), is the latest “in” ingredient. Everyone who is anyone is cooking with it, from Antonin Bonnet at The Greenhouse in London to Simon Rogan at L’Enclume in Cumbria.
At first glance, kelp might seem an unlikely choice. Why would anyone want to cook with leathery, olive-brown strips of dried kelp (Laminaria longicruris), let alone the fresh fronds of tangleweed? But kelp, and especially kombu, is a magical culinary ingredient. It intensifies the taste of savoury dishes, yet it is rarely seen by the eater. Thus, you won’t find the tiniest piece of kombu lurking on the plate of Darroze’s poached sea bass, for the kombu is infused into the poaching broth.
Kelp makes food taste better because it contains glutamic acid, which acts as a natural flavour-intensifier. The Japanese further enhance this quality by sun-drying their kelp. This ensures that the seaweed retains a little moisture and forms a powdery white dusting called mannite, which is particularly strong in glutamic acid. For this reason kombu is best when lightly wiped before use.
It does, however, require sensitive handling. Bonnet’s method is to make a light kombu liquid by first placing 20g of kombu in about three litres of soft mineral water. Next, he explains, “we set it over a low flame and remove it from the heat as soon as we see little bubbles rising to the surface, which is at about 90ºC. We then leave it to infuse for about 20 minutes, before straining.” Bonnet advises caution at this stage, for kombu releases bitter, unpleasant seaweed flavours if left for too long, boiled or cooked in hard water.
This sea-scented kombu broth can be mixed with other stocks or added to dressings. Bonnet, for example, mixes it with a pork consommé and reduces the mixture to make the sauce for his delicious pan-fried Arctic char with pork consommé, seashore salad and gyoza (pork dumplings). He also blends his kombu broth with wild herbs and grapeseed oil to create an intensely flavoured herb dressing for asparagus in the spring, or combines it with prawn stock for a prawn risotto with depth. Other chefs might infuse it directly into their finished stock or make dashi, the classic Japanese stock with bonito fish flakes.
Irish chef Richard Corrigan, whose restaurants include Corrigan’s Mayfair, believes that dried kelp, like other seaweeds, captures a certain zeitgeist. “It’s delicious, natural, wild and good for you,” he says, adding that in Ireland cooks have always used seaweeds, such as carrageen and sea lettuce, as well as kelp. In summer, Corrigan poaches brill with dried Irish kelp – “it makes a refreshing liquid to accompany the fish.” Its uses don’t end there, either. “If I’m really stressed out, I’ll infuse a mixture of dried Irish seaweed into a really hot bath and have a good soak. It’s wonderful.”
As with all culinary trends, the question is whether kombu, as well as other versions of kelp, will spread to the domestic kitchen. In one sense, it already has. Waitrose includes kombu in products from its Heston From Waitrose range, such as Heston Blumenthal’s Beef, Ale and Kombu Pie and his Ponzu Dressing. “We’re already looking at how to use kombu in other ready-made products,” says Neil Nugent, executive chef at Waitrose. “It really does make food much tastier.”
The test will be whether Waitrose and other supermarkets start to sell dried kombu itself. For, interesting as it is to infuse into broths, in my view it is even more delicious used simply as a seasoning on fish. It’s also very good infused into vegetarian dishes such as tomato consommé, where tinned tomatoes are drained through fine muslin, or a jelly bag.
An added benefit of kombu is that it reduces the amount of salt needed to season a dish. Try rubbing a tablespoon of sake into four 15cm lengths of dried kombu, leave to soften for 10 minutes, then place each piece between the flesh of two sea bass fillets (one fish per person) for no longer than 20 minutes. Then remove and grill or fry the fish without further seasoning. The result is the freshest, sweetest-tasting fish you can imagine.
Those keen to develop their kombu-cooking skills further should follow Shizuo Tsuji’s advice in his classic book Japanese Cooking, A Simple Art (Kodansha). His methodology can be easily adapted to western recipes. You can buy kombu by mail order, from Japanese shops and some health food stores – once you’ve tried it, you’ll come to depend on it.
Kombu is available to mail order from www.japanesekitchen.co.uk