A Real Cold Smoker?

[Bass Cadet]

Howdy, smokers!

I've owned a BSS for almost 2 years and have done a lot of smoking with it. Early on I built a PID with a timer controller to get good temperature control.



I haven't tried cold smoking yet. I was toying with the idea of setting up a thermoelectric cooler (TEC) inside the Bradley to cool it down but didn't quite work out the details. Recently I bought a small electronic wine cellar that has a built-in TEC. It supposedly keeps the wine at 50-66F.



So I had the idea of cutting it up and sticking the smoke generator in one side and venting to the other side.



Here's the full configuration. In a perfect world, the wine cellar would cool down the smoke below 60F, and the PID would regulate the temperature in the BSS. I was hoping to get extra smoke area by using the Bradley and the wine cellar. The combined volume is probably about the same as a 6 rack Bradley smoker.



Of course the smoke generator totally overwhelmed the wine cellar and the temperature ended up around 85F.  :(

Looking on the net, I found some people using a soldering iron in a can with wood chips/sawdust/pellets. I thought of doing this with bisquette dregs. With a 25-30W iron, the wine cellar TEC might just be able to keep up with it.



(Note: yeah, I'm using Bubba pucks to hold up the can :) I have to say this seems to be working. I am surprised how much smoke is generated. The Bradley bisquette particles work very well. Still some more experiments to be done, but thought I'd throw this out there.

[smokeitall]

That is a pretty nice set up.  It looks like you have plenty of room to add a couple shelves in that custom wine cellar and put a couple of bowls of ice in there.  That might help get the smoke a little cooler.  Or maybe one of those 10lb blocks of ice.

[Habanero Smoker]

Hi Bass Cadet;

Welcome to the forum.

I haven't had time to look at your setup yet, but it does look interesting.

[Bass Cadet]

Sometimes the simplest solution is to do what's been done before. Instead of extra TECs or soldering irons in cans, it occurred to me that I could just put the smoke generator in a cardboad box and have the box feed the wine chiller. It seems to work fine (smoking right now). 8)

[JGW]

I've been thinking about buying an el cheapo dorm fridge from walmart and cutting some holes in it to feed and exit smoke.  Moisture and condensation would be issues, but I think work arounds could be found.  Perhaps a little freezer would work better.

[classicrockgriller]

JGW, what about a small operating fridge (walmart cheapo) where u run an entry flex tube in one side (from the smoke) and snake it around before exiting the same hose out the other side...might cool it down to much. It could be insulated....damn adult beverages.

[Anongicy73]

I've always soaked the chips for my smoker - because the book SAID to soak for 30 minutes before putting the wood in the smoker box.  Now I'm hearing DON'T soak.  I'll try dry next time to see how it goes.  I usually
get about one hour's worth of smoke when I fill the box with soaked chips so I'll time the smoke next time to see how long it'll smoke with dry chips.  Fair enough???

In TBE or on the TEC, I don't soak before I smoke and it seems to work better in those units.  Of course, I'm using real wood chips - not the pellets some of these hi-brows are using.

BTW, my wife and I will be in Daytona next week for some R & R.  I'm taking you folks with me, too, so I can stay up-to-speed.

[Caneyscud]

You have several natural things going against you in the mini fridge idea. 
First and perhaps the biggest to overcome is that you are describing heat transfer by conduction.  Your are wanting to transfer heat from warm air through metal (or whatever the duct/piping is made of) into cool air.  Therefore you have two interface of contact conduction - both involving air.  As density decreases so does conduction.  Heat is transferred by conduction when adjacent atoms vibrate against one another, or as electrons move from atom to atom.  Conduction is greater in solids, where atoms are in constant contact. In liquids and gases, the molecules are usually further apart, giving a lower chance of molecules colliding and passing on thermal energy.  Not an efficient way of transferring heat. 

Second, geometry is against you.  I would assume you would use some sort of round tubing/duct inside of the fridge for smoke conveyance.  Circular piping is the most efficient piping - having the least exterior area per volume - but that is not good here.  That is working against you - the only spot that is transferring heat from an object to the ambient conditions is the exterior of the object.  The less area of exterior the less efficient the transfer.  particular in larger diameter piping like 4".  Think of a thick steak like the 1 1/2" thick rib-eyes I grilled last night - lots of volume in ratio to exterior surface even though it was not a sphere.  But guess what when I cut into mine - it was nice and red, juicy and still quivering inside while the outside was nice and brown - the heat had not had a chance to make it to the deep dark inner sanctum of the rib-eye sacellum - even though ambient on the fire side was probably 400+ degrees. 

Thirdly, consider Newton's Law of Cooling - it states that the rate of change of the temperature of an object is proportional to the difference between its own temperature and the ambient temperature.  The temperature differential is not great enough for there to be a particularly fast transfer of heat.  Might need a freezer rather than a fridge.

The challenge will be to convey the smoke through some some sort of small diameter, high transfer rate tubing (finned?) slow enough and long enough through a cold enough cabinet temperature that lots of the heat is transferred in a small amount of time. 

[Smokin Soon]

I have tried the ice thing with no success. The little box that Bradley sells called the Cold Smoke Adaptor did everything I wanted it to without increasing the temp. The hose setup is very fragile and they do need to fix that, but the unit itself works very well.

[Bass Cadet]

The wine cellar was meant to slightly lower the temperature. It seems to bring down the temperature 5-10degF or so from ambient. A cardboard box or cold smoke adapter can't drop the temperature below ambient. Ice in the bottom of the wine cellar could lower the temperature even more but I haven't needed it.

As far as the mini-fridge, Caneyscud sounds about right. It's been over 20 years since I took a heat transfer course, but laminar flow in a pipe would be mostly conduction through the pipe wall. The wine cellar, on the other hand, has an internal fan blowing across a multi-finned heat sink (see third picture above), so that heat transfer mechanism would be mostly convection.