Seaweed stock is largely underrated by most of us. It is used in Asia as a base for miso soup and for stews.
Traditionally in Japan, seaweed stock (dashi) is made only with Kombu and bonito flakes are added at the end. European seaweed stock often include different types of seaweed - whatever is on hand - and land vegetables and herbs (as below). You can use only kombu with the vegetables & herbs and the stock is delicious! The flavour is very delicate and won't change the taste of your dish.
3 liters of water
1 tbsp dried Wakame
5-6 strands Sea Spaghetti
5cm piece of Kombu strip or 1 tsp Kelp Granules in a tea ball
2 tbsp Karengo Fronds
2 Sea Lettuce Leaves
1 medium onion including skin for colour, sliced roughly
1 small carrot, sliced roughly
1 handful of dried porcini mushrooms
1 stick celery
1 cloves garlic + small piece of fresh ginger
fresh thyme, parsley & coriander stalks
Place all the ingredients in a large pot, cover and bring to a simmer slowly. Simmer gently for 1 hour. Cool & strain into a large bowl or jug. The pieces of seaweed and mushrooms can be chopped and returned to the stock if desired.