Typically, smoked fish is made using a purchased smoker or homemade, outdoor smokehouse. The smoke flavor is imparted to the fish by burning chips in the purchased smoker or burning wood, such as alder, apple or cottonwood, in the smokehouse. Liquid smoke is a way of imparting that smokehouse flavor to fish without having to smoke it. After you apply the liquid smoke, bake or grill the fish.
Mix up a brine or marinade. There are many different fish brine and marinade recipes available in cookbooks and online. As the name implies, all brine recipes involve salt. Brine is traditionally used with smoked fish. Some brine recipes also include brown sugar and other ingredients, such as pepper.
Either rub liquid smoke on the fish or mix it in with the brine or marinade. The technique used varies from recipe to recipe.
Place the fish in the brine or marinade and let sit. The length of time that the fish should sit in the brine or marinade varies per recipe. Usually, fish is left in a marinade for at least 2 hours. Fish can sit in brine for up to 36 hours.
Grill or bake the fish. Some recipes for baking the fish call for the oven to be set at a low temperature and the fish cooked for several hours. Others will have you bake the fish normally, for example, at 375° F for 10-12 minutes. Fish can be cooked on the grill at similar temperatures.