The main ingredients of a good brine for salmon are sugar and salt. Since salmon is a fish high in fat content, it does exceptionally well in a brine which has no additional fat, unlike most marinades. The salt and sugar both alter the protein in the fish, and allow it to easily absorb the water and spices. The combination of the salt, sugar and spices greatly enhance the flavor of the salmon and the brown sugar helps retain the moisture. Most classic recipes for brines recommend demerara brown sugar for its rich flavor and natural sweetness.
Measure sugar and salt and combine in mixing bowl.
Add spices and mix together.
Add soy sauce and water.
Mix all ingredients together until sugar is dissolved.
Place salmon fillets in mixture, skin-side down, making sure they are covered by the brine.
Cover and put in a cool place (preferably refrigerator).
Leave salmon in the brine for 24 hours.
Remove salmon from bowl, place on a rack and allow excess brine to drip off before cooking.