I just use the egg test for brine. It allows me to make any quantity that I want.
Take an egg (in the shell) and place it in a pot of water. It should sink to the bottom.
Don't use an egg that doesn't sink. Put as much water as you want in a non-reactive
container (I use plastic). Start adding salt (I use un-iodized salt, only because I can),
stirring to dissolve the salt. Put in the egg. Still sinks? Take it out and add more salt.
Keep doing this until the egg barely breaks the surface of the water, and you're good to go.
Now you can add brown sugar, pepper flakes, whatever, but no more salt. This does not
change the salinity. Put your fish in the brine. I brine for at least 12 hrs, but have done it
for up to 4 days, and it doesn't make any difference. Solutions can't be separated by
filtering, and the fish reaches an equilibrium and won't get any saltier. Refridgerating while
brining is a good idea, but if it's cool enough outside, just put it in the garage, or use
ice in bags. The salt in the brine basically stops any decomposition. It's sorta like
making lox and gravlox, except those are dry cures, and typically are not refridgerated
during curing.
