After brining for 8 hours remove salmon from brine solution, shake off excess and place salmon on a rack to drain (See Note 1).
Transfer to a parchment-lined baking sheet in front of a fan or in a well ventilated area to dry and develop a pellicle (shiny, tacky skin). Alternatively, leave salmon uncovered in the refrigerator to create a pellicle. (See Note 2)
Cut the salmon filet horizontally into thirds for easier handling and transfer pieces to a smoking rack sprayed with oil to prevent sticking. Note: If the filet doesn't have a pellicle, place the brined salmon on aluminum foil about the size of the fish to keep the smoke moving around the fish.
Gas Grill/Smoker (w/wood chips)
Add 1 inch of water to the water tray (or follow directions for your smoker). Add alder wood chips to internal smoker box (see Note 3) and smoke salmon for 4-6 hours, depending on thickness and size, fish should have an internal temperature of 145°F. On my gas grill I start the temp at 100°F for 2 hours, then 140°F for 2 hours and finally 175°F for the final 1.5-2 hours. Feel free to baste with the brine mixture each time you bump up the heat if you like. Smoke until fish reaches an internal temperature of 145°F.
Pellet Smoker
On a pellet smoker grill: because my Traeger pellet grill/smoker doesn't go lower than 165°F, I smoke for 4.5-5 hours (depending on thickness and size) and it comes out beautifully. Most filets I use are 3/4" to 1-inch in height in thickest part. As with everything, times may vary, so check periodically. Smoke until fish reaches an internal temperature of 145°F. Feel free to baste with brine mixture each time you bump up the heat if you like.
After removing smoked salmon from the smoker, allow it to rest on a cooling rack for an hour. Serve immediately or cool slightly, then refrigerate until ready to serve. Refrigerate wrapped in plastic wrap or a container and use within 8-10 days or freeze.
The pellicle creates a sticky surface on the fish for the smoke to adhere to. This step takes about 4 hours and is vital for properly smoked salmon.
Put wood chips in an internal smoker box, an aluminum loaf pan or even a bowl made out of tin foil. When ready to smoke, put the wood chip container on rack over hottest part of smoker/grill. Read more about this in my post on Smoker boxes and wood chips for smoking.