Smoked meats have a more distinctive flavour and a longer shelf life than unsmoked meats. Bacon and smoked salmon require cold smoking, which means the meat is exposed to temperatures between 26 to 38 degrees C (80F to 100F) for varying lengths of time. You can buy a cold smoker device or, with a little time and ingenuity, you can also build one yourself.
Set up the barbecue grill and the cardboard box next to each other.
Cut a hole in the top of the cardboard box about the diameter of the tubing you'll be using.
Tape the fan to the hole on the inside of the box and attach the power source. You can use a mini-fan or even an old computer fan for this job.
Position the tube so that one end covers the hole in the box and the other end covers the grill's vent. You don't have to tape the tube anywhere -- you'll want to move it out of the way easily so you can access the box and the grill.
To create the smoke, soak whatever wood you're using in water, then place the wood in aluminium foil. Fill the grill with hot charcoals and then place the packets in the grill to start the smoking. The fan will pull the smoke through the tube and into the box.
Use towels to help seal the smoke in the box. Wash the towels several times afterwards to get rid of the smoky smell.