Why has my cold smoking stopped working? I bought a cold smoke generator for a small meat smoker last year and the first go with 3 dry brined mackerel worked GREAT!  But the next 4 attempts have FAILED.  The meat has come out translucent and oily like lox, and tough.  Not opaque and whiteish like the cold smoked mackerel I buy from my Polish baker.  (I think he gets his from Canada) I thought perhaps the first batch I did succeeded because they were smaller but my last batch I fileted and got the same result.  I dry brine OVER 24 hours in 1 part brown sugar and 3 parts kosher salt.  Completely covered.  I even tried brining TWICE on the last 2 batches.
The fish have been very fresh in all cases and my temperatures have been below 60 F in all attempts but the 2nd.
Please help.  I wouldn't be so distraught if it hadn't worked PERFECTLY once, before I knew what details to pay attention to.
It sounds like you may be over-curing the fish. The salt and sugar draw water out of the fish, the longer it's applied the more is lost, and you can go too far. When I cold smoke a side of salmon it's only cured overnight, say 8-10 hours, not for a whole day.  I imagine there wouldn't be much left after that.
Try reducing your dry brining time to 4 hours, then rinse, pat dry and let them dry out overnight in the refrigerator.