johnmeyer
Master of the Pit
Let me answer your question by first showing my popcorn can setup (again):
I smoked a small amount of Costco sharp cheddar cheese. I have Jeff's Hickory sawdust. I filled one row in my 5x8 AMNPS, lit it, let it burn down for ten minutes, and then started the smoke. It took about 2.5 hours for the sawdust to burn to the end of the one row. I monitored the temperature both inside and outside the smoker, and there was never a measurable (more than 2 degree) difference during the whole smoke, and most of the time the temperatures were identical. Also, the second section of my short duct work never got even the slightest bit warm. Air temperature during the whole smoke was 60 degrees.
The cheese turned out absolutely great, and was edible right away. Nothing but authentic smoke flavor. The only thing I would do differently next time would be to use a wood that better matches the flavor profile of cheese. I think Hickory is a little too strong.
BTW, on two prior occasions I had tried cold smoking cheese with the AMNPS placed inside the MES. The result was pretty awful, even when using sawdust.
I inspected the second section of duct work which I had cleaned, prior to the smoke, in my ultrasonic cleaner so that its interior was spotless. After the smoke I looked at it, and could not see any visible deposits or color change whatsoever.
I have done other normal (hot) smokes since then, always cleaning the duct and "mailbox mod" in my ultrasonic cleaner each time. This lets me see exactly how much gunk is being precipitated out of the smoke. After each smoke, the can is absolutely loaded with black shiny, oozy gunk, as is the first 6-10 inches of the duct coming out of the can. After that, there is almost nothing on the inside of the remaining duct.
So this is why, for my setup, I see no reason to pursue adding long sections of duct. I am sure that I might get some additional precipitation on the interior surfaces of any additional sections, but based on my own observations the improvement is going to be really, negligible. Using the old Pareto 80/20 rule, I'm getting almost all the benefit with my large surface area can (better than a mailbox) and two sections of duct. To put numbers on it, I suspect that I'm probably getting 95% of the benefit with the current setup compared to adding 5-10 feet of additional duct.
So, as I said before, my recommendation is to use your current setup a few times and monitor the residue left behind in the duct that you have, and also put your hand on each section of duct during the smoke and see how hot/warm/cold it feels. If the last section still feels warm, and if it shows quite a bit of smoke residue, then you can probably still get some improvement by adding more duct. By contrast, if it is cold and still looks pretty clean, it is hard for me to see how you'd get much improvement by adding a lot of additional duct.
I really like my current setup because I can put the duct inside the can, and store the can inside the smoker. I can then roll the smoker around to where I actually do my smoking, carrying everything I need inside the smoker.
