Condensation on top (inside) and acid rain problem

Discussion in 'Other Builds' started by busmania, Apr 17, 2016.

  1. busmania

    busmania Smoke Blower

    i built what is basically an upright smoker (firebox on bottom, compressor tank welded Verticle). I'll start a thread on it this week. The basic design is below. Anyway, fired it up for the first time this weekend and it worked great except for one issue. It condensed so much moisture on the top that it kind of rained down on the food creating small black pools (gross...I cut off those pieces of meat). Anone know what could cause this? It ran great except for this problem. I did not use a water pan. Any thoughts?

  2. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    You may not have preheated the smoker to above cooking temp.....   The smoker cooled down during the cook so condensate could form....   You were cooking "brined" meats and they gave off the moisture....   The wood had moisture in it....    Fire/combustion of any kind gives off water...   Water is a product of combustion....  

    Insulate the smoker and keep it's temperature higher....    I'm guessing there is an exhaust stack on top of that CC that you are not showing us in the picture.....   The exhaust cools and drips condensate....   Putting an exhaust in the center of the top is not good...   put it  out the side....
  3. busmania

    busmania Smoke Blower

    Yes, exhaust is indeed on top middle. I am thinking the air cooled before exiting. Stack too short maybe? When you say to put the exhaust on the side, any other tips? Wher on the side? Still exiting the top? Thanks Dave.

    Oh, this may or may not matter, but it was snowing outside so it is possible the cc did cool down during the coarse of the cook. That said, I maintained 250-275 most of the cook.
    Last edited: Apr 17, 2016
  4. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Exhaust too long.....  short and out the side at the top of the side wall of the CC.....  Insulate it...  run it on a down hill slope so condensate does not run back into the smoker...  Not enough air flow, thru the smoker, to remove the moisture..

    All smokers need good air flow to get rid of the moisture....
  5. busmania

    busmania Smoke Blower

    The stack is only 4" long with an inside diameter of 4". I am confident air flow is not an issue (but could be wrong of course). I'll mess with the exhaust first. I may even try no exhaust. With heat rising, I actually think it may run ok with no exhaust. I'll try that and if it doesn't work, I'll re route it to the side. I think your initial point about the cc cooling off could be a big part of it due to the cold outside temps. And now that I think about it, there were times the cc didn't even feel warm which at the time I did think was odd. Oh, I also had the exhaust half blocked off because I thought there was too much air flow. After I noticed the drippings, I opened the exhaust fully. So many variables.
  6. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    So many variables is spot on....  Let us know what solves your problem so others may learn.....    Thanks....

  7. busmania

    busmania Smoke Blower

    I Most definitely will update this when I figure it out.

    Two more questions. If I use a water pan, it still should not condensate, correct? I may just do several test runs with no food till I figure it ou...but I'll need something to create moisture.

    Second, if I redo the exhaust out the side, should I do a smaller diameter pipe like 3" instead of 4"? The exhaust was the only variable I was unsure on for the build so I actually haven't even welded it on yet. I knew I'd have to make changes.

    Specs. 17 x 17 x 19" fb. 60 gallon tank.
  8. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Looks like you heat with wood.... Sooo, I would stick with the 4" exhaust ... If your smoker is air tight, it should be, you won't have any problems...   If you have air leaks in the door, it will suck in outside cold air and cool the smoker...   Try a "high temp" silicone door seal...   Silicone on the door seal and saran wrap on the smoker...   close the door and let it cure...   silicone won't stick to the saran and it will make a perfect "fit in place" gasket...
  9. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    Dave has given you some good pointers here and I think that the cool outside temperature was probably the cause of the high levels of condensate, however it would be useful to have some more information.

    What were you smoking and how long were you smoking it for? You mentioned that the CC maintained 250-275 F for most of the cook - did it fall significantly below this at any point or at the end before you took the meat out? Where were you measuring the temperature? With such a tall CC it is possible that you are getting quite a temperature gradient as you get higher up. Next time you may want to also take the temperature of the gasses in the flue to see what the temperature is at the top of the smoker. If they are significantly lower then the CC will be acting like a big reflux condenser.

    I would not use a water pan in this setup. The water is really acting as a heat buffer to smooth out temperature spikes in the fire box from reaching the CC. Use the pan but fill it with sand instead of water and it will do a better job and will not cause any additional humidity. Were you using it during this smoke?

    Dave may be right about the position of the flue but as your smoker is really the same concept as the WSM I am not so sure. This has the exhaust vents at the top and does not even have a flue. In an offset smoker the flue is required to draw the hot gasses sideways through a horizontal cooking chamber whereas in your smoker the heat is doing what it does naturally - it is rising. Before you make any structural changes I would try other, less invasive, things first.

    As Dave also mentioned, in the cooler outside temperatures some insulation could help to reduce the heat loss through the CC walls that is contributing to a temperature gradient towards the top.

    A few suggestions to try:
    • Make sure you cook the meat on the racks at the top of the CC and ensure that the desired temperature is maintained there. That way you will know that you don't have the top of the CC cooler than the cooking area, allowing condensation to form.
    • Measure the temperature of the gasses as they come out of the flue. This will also help you to check the temperature gradient.
    • Use sand in your water tray in place of the water.
    • If the meat is not cooking on the top rack then place a ring of foil or a foil tray on the rack directly above to prevent any condensate that may form at the top of the chamber from dripping on to the meat.
    • In cold weather place a welding blanket over the CC to help insulate it and help prevent the chamber walls from cooling too quickly
    It takes time to get to know any new smoker and I am sure that you will soon master this one [​IMG]  
    Last edited: Apr 18, 2016
  10. hakamo0o

    hakamo0o Fire Starter

    I would say that because your fire box is at the bottom and you have a "sort of" tall cooking chamber; it is acting like a heat exchanger.

    By the time your smoke reaches the stack at the top, it is cooled down due to heat loss from the chamber walls; which leads to condensate.

    I had a similar problem with my double barrel but luckily I noticed it during my rigorous testing phase (5 test runs using around 60 lbs of charcoal). I notices some condensation in the cooking chamber near the chimney area (specially on a cold windy day). After I insulated the barrel using glass wool; there is no condensation anymore.

    I would advice you to wrap some insulation around your smoker and as mentioned above; put an empty tray on the top most rack to collect condensate if any.

    Another thing; using insulation save me a lot of charcoal, I just smoked half a goat using only 2-3 lbs of charcoal. While without insulation I used 6 lbs of coal to smoke 2 lbs of chicken wings!!

    Hope that helps

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