I have done hot smoked salmon on the BGE before, but I wanted to try my hand at cold smoking before the weather got too hot here. We went to Harry's Farmers Market (basically a Whole Foods) to snag some really nice salmon. It was a bit pricy for a piece of a filet, but we don't eat smoked salmon all that often. I figured it was worth the splurge, so we got about a 1.5 lb piece of farm raised salmon.
Based on my completely unscientific experiences with salmon, I tend to find that farm raised salmon has more fat. To me, this fat tends to make for a more tender fish and lends a buttery flavor to the finished product. I have read that the farm raised salmon tend to have a more rich diet than wild and this is the reason for the higher fat content. Whatever the reason, the farm raised salmon I can get near me tends to be better than the wild salmon that I can get.
After getting the salmon home, I knew I was going to need about 3 days or so for the whole process. This was a Sunday, so I really wasn't ready to start. I threw the salmon into the freezer for the next weekend when I was planing to take some time off to have a 4 day weekend. Later I found out that one of the pages I was using for guidance around the smoking process actually recommended freezing the fish to make a more tender end product. See? Laziness isn't always a bad thing...
That next Thursday evening, I thawed the salmon on the counter, and made up a salt/sugar mixture that I had used before with smoked salmon that I saw Alton Brown use. You can find the recipe at http://www.foodnetwork.com/recipes/alton-brown/smoked-salmon-recipe.html. Just scale the mixture for the amount of fish you have.
I then laid down some plastic wrap on top of some foil, and then spread half the salt mixture on the wrap. Then I placed the fish on top of the salt mixture and covered the fish with the rest of the mixture. Then I sealed the fish and salt in the plastic wrap, and then closed the foil tightly around the whole thing. I then made sure to put the fish in a glass dish to catch the juices, and wrapped a brick in plastic wrap and placed it on top of the fish. I then put all this in the fridge.
Then until Saturday evening, I let the fish cure in the salt. About every 12 hours, I flipped the fish packet over to make sure to get the salt evenly soaked into the fish. On Saturday evening, I then removed the dish from the fridge, opened up the packet, and rinsed off the salmon with cold water. There were still some peppercorns from the salt mixture attached to the fish, so I left them. I patted the fish dry, and put it on a clean plate. I then put the plate back into the fridge, uncovered, to let the fish dry out for about 12 hours. The fish would be ready to smoke on Sunday morning.
That day, I stopped by the local mega do-it-yourself store, and picked up the materials to build a cold smoke attachement for my Big Green Egg. I wanted to keep the temperature low for the smoking process to make this a cold smoked salmon. I followed the instructions at http://www.nakedwhiz.com/coldsmokingcan/coldsmokingcan.htm to build the attachment.
On Sunday morning, I put 3 pieces of charcoal into my smoker can, and got them started. I then put 2 big chunks of apple wood on top of the burning charcoal, and attached the lid to the can. I put the dryer vent into the air vent at the bottom of my BGE, and made sure I was getting a good amount of smoke. I then pulled my salmon out of the fridge, and put it on the grate in the BGE. I attached my remote thermometer to the fish, and closed the lid. I basically was following the guide at http://www.newenglandprovisions.com/coldsmokedsalmon.html to finish the smoking process. Basically I just wanted to make sure that the fish stayed under 70 degrees Fahrenheit while smoking it. After about 30 minutes, the fish started getting above 60 degrees, so I removed a piece of the charcoal from the can, and opened the top the BGE to vent some of the heat. After another 30 minutes, the fish was at about 64 degrees, and I frankly just couldn't wait any longer.
We pulled the fish off the BGE, and then let it rest for just long enough for us to toast some bagels. I cut off a slice or two to try while the bagels were toasting. The first couple slices were of the outer surface of the fish. Those slices were fairly salty, and somewhat stiff. As I sliced further in, the fish was much softer, and the salt level was perfect. These center slices still had a nice level of fat, and the fish tasted like buttery smoke with just the right level of salty sweet.
We wrapped the remaining fish in plastic wrap, and put it back in the fridge. I know exactly what I am having for breakfast tomorrow.