AMNPS, Cold Smoking, White Smoke, Mailbox Mod

[baseballguy99]

I’m trying my hand at smoking some cheese today.

Outside temps are low 30’s. I have a mix of hickory and corn cob pellets in the AMNPS in a mailbox mod.

I lit the pellets the same way I always do when hot smoking. I am cycling the unit on and off keeping the ambient temp around 60*.

All I am getting is a thick white smoke. I also noticed when I was doing some salmon last week all I was getting was white smoke (Smoking between 125-145).

When hot smoking (225*+) I get perfect TBS.

I have tried the AMNPS at varying depths in the mailbox, I have tried the chip tray in different positions. None of these seem to help.

Can anyone provide me with any other suggestions? TYIA!

 

[SonnyE]

Is your fuel dry?
daveomak suggested putting pellets in the smoker for 24 hours at 275.
I did some and was pleased at how much steam came out. (Had to be steam, because there wasn't anything else making smoke.)
It has worked out great for me to use my smoker/oven as a drying kiln for my fuels.

Recently I was running mine to dry and sterilize it. I thought, heck why not put a pan of pellets in to bake?
Ya know, my pellets are kind of getting Golden Brown... :confused: :)

Also, due to your low temperature, maybe try the tray in the MES?

 

[gmc2003]

How are you lighting it? You have to get the pellets lit and stay lit for about 10 min.. Then blow the flame out and let them smolder. I usually put amps into the smoker when I know they are really smoldering and not going out.

Chris

 

[tallbm]

I’m trying my hand at smoking some cheese today.

Outside temps are low 30’s. I have a mix of hickory and corn cob pellets in the AMNPS in a mailbox mod.

I lit the pellets the same way I always do when hot smoking. I am cycling the unit on and off keeping the ambient temp around 60*.

All I am getting is a thick white smoke. I also noticed when I was doing some salmon last week all I was getting was white smoke (Smoking between 125-145).

When hot smoking (225*+) I get perfect TBS.

I have tried the AMNPS at varying depths in the mailbox, I have tried the chip tray in different positions. None of these seem to help.

Can anyone provide me with any other suggestions? TYIA!

I think what you may be running into is a build up of smoke that becomes stale.
It builds up and looks really thick and white. I bet if you pull your AMNPS out it will be producing smoke the same way it does regardless of a hot or cold smoke but the difference is how the smoke is lingering now that you have little to no draft.

I built a simple little device to help cause draft with my cold smokes. In short it is a cardboard tube with a computer blower fan that blows air up the tube. I place the tube over the vent of my MES and instant cold smoker assist to deal with the issues you are experiencing. Here is a link to the device but feel free to read the whole thread:
Another MES Mod - Cold Smoker Assist!!

here is the image of the device:

 

[baseballguy99]

Is your fuel dry?
daveomak suggested putting pellets in the smoker for 24 hours at 275.
I did some and was pleased at how much steam came out. (Had to be steam, because there wasn't anything else making smoke.)
It has worked out great for me to use my smoker/oven as a drying kiln for my fuels.

Recently I was running mine to dry and sterilize it. I thought, heck why not put a pan of pellets in to bake?
Ya know, my pellets are kind of getting Golden Brown... :confused: :)

Also, due to your low temperature, maybe try the tray in the MES?

The pellets are stored in air tight containers and I have not had this problem until now. Maybe I will try again tomorrow and microwave the pellets before and see how that work.

How are you lighting it? You have to get the pellets lit and stay lit for about 10 min.. Then blow the flame out and let them smolder. I usually put amps into the smoker when I know they are really smoldering and not going out.Chris

The same way I always light them and haven’t had a problem until now. I torch them for a good minute until I have a large flame. I then let it burn for 10 mins or so (if the flame goes out I either relight it or blow on it until the flame starts back up). Then I blow the flame out and blow downward to get a nice bed of cherries. Then I put the AMNPS in the mailbox about halfway back.

I think what you may be running into is a build up of smoke that becomes stale.
It builds up and looks really thick and white. I bet if you pull your AMNPS out it will be producing smoke the same way it does regardless of a hot or cold smoke but the difference is how the smoke is lingering now that you have little to no draft.

I built a simple little device to help cause draft with my cold smokes. In short it is a cardboard tube with a computer blower fan that blows air up the tube. I place the tube over the vent of my MES and instant cold smoker assist to deal with the issues you are experiencing. Here is a link to the device but feel free to read the whole thread:
Another MES Mod - Cold Smoker Assist!!

here is the image of the device:

Thanks for the advice. I will try a few things and if nothing else works I will look into giving something like that a go!

 

[chopsaw]

How clean is the tube ? Mine had some gunk on the bottom that needed to be cleaned .

 

[baseballguy99]

How clean is the tube ? Mine had some gunk on the bottom that needed to be cleaned .

Tube? I am using the tray.

 

[chopsaw]

My bad . I got you mixed up with another thread .

 

[SonnyE]

The pellets are stored in air tight containers and I have not had this problem until now. Maybe I will try again tomorrow and microwave the pellets before and see how that work.

Mine are too. But I still dried the peadoodly out of them.
You've not had this problem before... Have you run at these cold of temperatures before?
I tried the microwave, myself. But realized it just warms the water, doesn't draw it out.
Baking a pile does dry it out.
If you do a run tomorrow, try with the pan inside and watch the smoke coming out.
I've seen it suggested to draw out the chip feeder a little to let more air in.
Air in, smoke out.
I also put a stack on mine to create more draw.

 

[daveomak]

Do you have good air flow through the mailbox ???

This works really well..... upper hole is to stop the smoke from recirculating... recirc smoke is low in oxygen..adding legs helps the AMNPS get air for a good clean burn...

...

 

[baseballguy99]

Dave, I based my mod off your design. 2 differences though. I have 3 holes on the bottom and I used binder clips to raise the AMNPS tray off the bottom.

Do you think I should cover 1 hole and raise the AMNPS up a little more?

 

[daveomak]

I'm befuddled... Are you burning the same amount of pellets, per hour, during the white smoke event ??
During the extreme cold, if your duct from the smoker to the MB is not sealed totally air tight, the cold heavy air will reduce the air flow through the MB .... reducing the combustion process..
Blue smoke at 225 and white smoke at 125 "appears" to be a problem with air flow... warm air sucking harder because it is lighter.. SWAG here... enlarge the holes in the MB door... more holes won't help that much.. they "may" need to be bigger.. a step drill is in order...
I sure did put a lot of words together to not say much ...

 

[baseballguy99]

The pellets did seem to burn a little slower and not fully burn (small black chunks instead of white ash).

I did notice a lot of condensation on the inside of my window after a 2hr smoke on the cheese.

I guess I’ll just keep trying different things to see what works.

 

[SonnyE]

The pellets did seem to burn a little slower and not fully burn (small black chunks instead of white ash).

I did notice a lot of condensation on the inside of my window after a 2hr smoke on the cheese.

I guess I’ll just keep trying different things to see what works.

Just thinking out loud here, but could the door of the mailbox be left open a tiny bit?
Say, 1/4" at the top, for more airflow before enlarging the holes?

And yeah Dave, step drills like that (Unibit) are the way to go anytime holes are being installed in sheet metal.
Where you have your elbow at the vent is where I put my stack (3" X 24" tall), to get a natural draw on the box.

 

[daveomak]

Black pellets are a sure sign of "lack of oxygen"... You are making charcoal if the pellets turn black... I think the "weight" of the cold air and it's density are being restricted by the small holes in the MB door...
FWIW, the sharp edge of the holes creates a "vena-contracta"... The sharp edge effectively reduces the size of the hole to maybe 3/4 of it's desired diameter, reducing the air flow by 50%.... Therefore, over sizing the holes is necessary to achieve the desired air flow...

...

 

[baseballguy99]

Dave, if I make the holes larger for cold smoking will it affect the way it works on hot smokes?

 

[SonnyE]

I'm following this like flies on dog doo!
Because I've gotten black pellets as well.
But at higher box temperatures, I get ash. Complete burn.
So I'm learning I need more air to my 'Mailbox'.

 

[johnmeyer]

Has anyone attempted to do tests, using some sort of vent control like you have in a traditional Weber charcoal grill, to try to determine the optimal total area for the air intake holes on a mailbox mod? I guess I should just finally mod my own mod and add some sort of adjustable damper, and find out for myself, but I'm feeling lazy, so I thought I'd just ask.

Actually, this thread may prove what I always suspected, namely there may be no single, correct size, and that when cold smoking, you may need more holes, or bigger holes, because of the lack of vigorous air draw (due to lack of heat), whereas when cranking 'er all the way up to 275 (my MES top temp), a smaller hole size might be better because that heat will cause the air to be vigorously sucked out of the mod and through the smoker.

I have four holes in the bottom of my mod, and I know that their total area is a LOT larger than the holes in the original MES chip loader. However, the goal here is to get a complete burn in the AMNPS, and perhaps that requires a lot more air than what Masterbuilt thought was needed when they designed the chip loader holes.

What's more, a lot of those science articles linked to in a recent thread suggest that without sufficient oxygen, the smoke taste won't be too good, regardless of what color comes out the exhaust. It is interesting to read the posts above which suggest that "creating charcoal" with the chips in the AMNPS may be a sign that you are not getting very good smoke.

 

[baseballguy99]

I didn’t cold smoke anything today but I did do a pork butt and some ribs @275*.

I microwaved the pellets for 30 second intervals a couple times. It seemed there was some “steam” coming off of them. So I threw them into the oven for about 45 mins.

I did notice that lighting them with the torch seemed to be a lot easier and the Cherry seemed better. So I think I will continue to dry them in the oven or smoker while it’s heating up.

 

[baseballguy99]

Black pellets are a sure sign of "lack of oxygen"... You are making charcoal if the pellets turn black... I think the "weight" of the cold air and it's density are being restricted by the small holes in the MB door...
FWIW, the sharp edge of the holes creates a "vena-contracta"... The sharp edge effectively reduces the size of the hole to maybe 3/4 of it's desired diameter, reducing the air flow by 50%.... Therefore, over sizing the holes is necessary to achieve the desired air flow...

View attachment 354817 ... View attachment 354818

So Dave, looking at the picture I should use the step bit and drill from the inside out?