To step back a bit, when you hot smoke food you're cooking it at higher temps such as 100C or above. You're adding smoke to the meat, but you're also cooking the food. With smoked salmon you use cold smoking, which is at 37C or below! The fish is cured, smoke flavour is added, but you don't need to cook it with heat. If the temperature gets too high then that will change the texture of the fish. It'll still be delicious, but it's not what we think of as smoked salmon.
Some people come up with contraptions involving a firebox attached to a long hose, and sometimes involving passing the smoke through ice. This tries to make sure that the smoke doesn't get above the 37C barrier. After a bit of thinking I figured out that I could use a soldering iron to get the wood chips to the smoking point without getting fire going.
This recipe happens in parts. First you cure the salmon in the refrigerator for 2-3 days, then you dry it for up to a day, then you smoke it for about 4-6 hours. So depending on how thick the salmon is and how impatient you are, this takes between 3-5 days to make, even though the actual work involved is minimal.
Step 1: Prepare the Cure
125g kosher salt
100g white sugar
50g brown sugar
6g pink salt (see note)
Mix it all together in a bowl. That's it.
Note: Pink salt, aka DQ Curing Salt AKA Instacure #1 is a preservative. It's salt and nitrites, dyed pink to avoid it getting confused with other stuff. Since the salmon will be sitting at room temperature while smoking, this is a guard against nasty things growing on it. I'm sure you could do it without, though the stuff is cheap, plentiful, and easy to obtain (I ordered mine online but have later found out you can get it from most butchers that make their own sausage). If you do use it, please make sure to keep the bag sealed and away from kids as in large quantities it's poisonous!
Step 2: Prepare the Salmon
Place some plastic wrap over the salmon.
Have a scotch... You're halfway there.
You'll need to gently press down on the salmon as it sits in the fridge. A board, plate, pan, or anything else will do nicely. Put some weight on it. I normally use canned goods, but since I'm submitting this as part of the kitchen power tool challenge I thought I'd amp it up a bit and weight it down with power tools.
Put it in the fridge, it'll sit for 2-3 days. The fish will be firm and you'll see a lot of liquid has left the fish. It's ok to leave the liquid in there while the fish sits, you'll take care of that later.
Step 3: Make the Smoker
My can looked untreated, but just to be careful I burned the can for a little while.
Step 4: Rinse and Dry the Salmon
Step 5: Smoke!
The fish goes in your BBQ and the smoker goes below. You don't want the fish on top of the heat source, you want the can to fill the cavity of the BBQ with smoke. If your BBQ has a lot of holes you can cover them up with a towel.
Close the lid, turn on the soldering iron. Shortly smoke should be coming out and will start smelling like awesomeness.
Smoke for 4-6 hours, depending on how smoky you like your food.
Take out and enjoy.
You can keep the fish, wrapped in wax paper, in the fridge for about a week. If it lasts that long!