Begin by cutting away the fins and chop the bones into even smaller pieces.
Now remove the eyes and gills from the head and chop it into even smaller pieces as well. Then rinse everything under some running cold water till the water is clear.
Once it's clear drain the water and let it drain for a couple of minutes.
Transfer the rinsed bones on a metal tray and add the onion and the garlic. Bake the bones at 180 °C (356 °F) for about 30 minutes.
Meanwhile cut the celery.
Then transfer the bones into a pan and deglaze the tray with the white wine. Let the tray soak in the oven for a couple of minutes before pouring it into the pan as well.
Also add the chopped celery, the coriander seeds, the black pepper, enough water to submerge the bones and the flat parsley. Let the broth simmer on a low heat for 45 minutes.
After that pass it through a fine sieve and let it drip for at least 30 minutes, so you don’t waste a single drop.
Then reduce it till you’re happy with the flavour. You want a very intense base.
Once you’re happy with the result weigh the total weight and add a gram of agar for every 100 grams of base. I had 250 grams, so I added 2.5 grams of agar.
Mix it well and bring it to a boil for at least 30 seconds. Then pour it into a bowl and let it cool down in your fridge.
When it has set transfer it into a blender and blend it into a lovely gel.
To bring it to the next level I always vacuum it. Do this in a vacuum chamber at a 100%, this will result in a clear and more intense gel.
Now transfer it into a piping bottle and keep it in your fridge for later. Just beware that because there’s a lot of gelatine from the fish bones, the texture will be different when cold.Â
