In researching cold smoking a product there is quite a large gap between 80-100* . Does anyone use a more exact temperature? Does it vary because of the product? Any little hints to give the smoking a bit of a spicy kick into the final flavour?
The person who wrote this, agrees with you on the 80-100° part. However, in his salmon recipe, he advices to smoke below 85°.
So my guess is that it depends on the food you're smoking.
The purpose of cold smoking is to preserve meat and add smoke flavor without actually cooking the item being smoked. The amount of smoke kills bacteria and creates a harsh environment for more to go. So the temperature of the smoke doesn't really matter as long as it isn't hot enough to cook the meat. That is why in cold smokers there is large amount of cooling tube between the fire and the actual meat and why you still cook things like bacon and ham before consumption. My rule is as close to room temp as I can get it, with out having an excessive amount of tubing, as I find the meat takes the smoke better at those temps and I run no risk of rendering any of the fat.