Make the brine: In a large bowl, combine water, salt, and brown sugar. Stir until the salt and sugar are fully dissolved.
Add flavorings: Mix in peppercorns, bay leaves, garlic, lemon, and herbs for added aroma and depth.
Brine the fish: Submerge the fish fillets completely in the brine. Cover and refrigerate for 4 to 8 hours, depending on the thickness of the fish.
Rinse and dry: Remove fish from the brine and rinse gently under cold water. Pat dry thoroughly with paper towels.
Air-dry: Let the fish rest uncovered in the refrigerator for 1–2 hours to form a thin tacky layer (pellicle), which helps the smoke adhere.
Smoke the fish: Smoke according to your smoker’s instructions until cooked through and smoky-flavored.