What with Christmas round the corner, I decided to cold smoke some salmon. Thought I'd record the process here in the hope of starting discussion that will help me improve my technique. Sorry if this isn't the right section to discuss cold smoking, there didn't seem to be anywhere else it would fit!
I unfortunately had to commit a cardinal sin and rush through the process, as I started too late and I was smoking a piece for a friend who needed it by Monday morning to take away with her.
Started on Saturday lunchtime with two good big salmon fillets, just over a pound each. I laid them skin side down on a bed of salt in a pyrex roasting tray, then covered the top in a thick layer of a 1:1 mixture of salt and sugar. I left them outside in the smoker (it's cold enough) for six hours, by which time they had dumped a lot of water and felt quite nice and firm. Actually, one of them did, the other I think could have done with longer, but I didn't have the option.
Next came the drying process. This bit, I stuffed up. I put them outside in the smoker overnight. The smoker was too damp inside from recent rain, and this combined with the lack of air circulation, meant the fillets didnt develop the pellicle needed for smoking. So, this morning, I had to leave them outside in the breeze for a few hours to dry a bit more. Again, they could have done with a bit longer, but I didn't have that luxury.
Into the UDS, with my crude CSG attached, which requires constant attention to keep the wood topped up and in contact with the coal. Added a sprinkle of demerara sugar and fresh cracked pepper. I managed 8 hours smoke before the embers died out. I wanted to do more, but I am pooped after a long few days preparing things for Christmas and didn't fancy lighting another fire.
I have tasted a little slice, but it is of course premature - I find cold smoked food tastes bitter and unpleasant immediately out of the smoker. I've wrapped it in baking parchment and popped it in the fridge to allow it to mellow out and the smoke permeate the fillets. I may resmoke my fillet if it needs it, but I think it will be ok. I'll try it tomorrow with breakfast, and reassess.
I also smoked 3 slices about 1/3" thick of gruyere, and three patties of butter. The cheese I gave about 3 hours smoke, the butter about 2 (the smoke was quite light during the butter smoking phase, or I would have smoked it for a half hour to an hour).

