I have previously written about how you can cook a perfect steak with a simple DIY sous vide technique. Of course low temperature cooking applies equally well to fish with the only difference that the temperature can be turned down even lower.
A slightly different approach for cooking fish was presented by Haqvin Gyllensköld in the Swedish book “Koka, steka, blanda” from 1977, which I became aware of through Östen Dahlgren’s book “Laga mat – hur man gör och varför”. In stead of keeping the fish at a constant temperature (which requires quite some attention unless you have a thermostated waterbath), in this method, as the hot water cools, the temperature of the fish increases until they’re at the same temperature.
This is how you do it:
- Weigh the fish
- Boil the triple amount of water
- Add some salt to the water (15 g / L)
- Put the fish in the water and remove the pot from the stove
- Check the graph below for how long the fish should be left in the cooling water