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Make: Projects – Hot to cold smoker conversion
cold_smoker_parts.JPG

This is a simple kludge, really, but it’s worked out remarkably well, considering I knocked it together in about 40 minutes 5 years ago and it’s seen almost monthly use since then. What I started with was a pile of junk grill and smoker components, most of which came from a Brinkmann “Gourmet” smoker (as shown below) that my mother once accidentally set on fire. Lots of electric smokers have this three-part lid/body/base construction, however, and the exact make and model are not important.

brinkmann_electric_smoker.jpg

Tools

  • Hand drill
  • 3/8″ bit
  • Handheld jigsaw
  • Tin snips
  • Rubber mallet
  • Screwdriver
  • Chalk or permanent marker

Materials

  • Electric smoker lid (A)
  • Electric smoker body (B)
  • Electric smoker base (C)
  • Extra lid to fit C (D)
  • 4″ Corrugated aluminum dryer vent hose, about 72″ long (E)
  • Sun-dried tomatoes (F)
  • Garden cart to house all of the above (optional) (G)
  • 2 x hose clamps to fit around E (not labeled)
  • 2 x 4″ duct start collars to fit E (not labeled)

Step 1: Cut duct holes

Hole cutting diagram.png

4″ diameter circular holes are required in the extra lid (D) and the smoker body (B). Locate them by positioning the base of a start collar on the surface and tracing around it with a piece of chalk. The exact positioning of the lid hole is not very important, but the hole in the smoker body needs to go as close to the bottom edge as possible. Once you’ve traced two circles, drill a 3/8″ hole well inside the perimeter of each. It may be easier to step drill, starting with a small (say 3/16″) bit and working up to 3/8″ in one or two steps. The hole does not have to be clean, as it’s going to be in the waste section, anyway.

Now insert the jigsaw blade in each of the holes you just drilled and cut out the 4″ circular openings you’d previously traced. This is liable to be very loud, so be sure you’re protecting your ears as well as your eyes, fingers, and hands. If the cut edge comes out very rough you might take a minute to smooth it out with a file.


Step 2: Install start collars

duct-start-collar.jpg

This is the start collar that connects the duct to the smoke generating and receiving vessels. It is not the exact same model I used, but functionally it is identical. Installation is straightforward: Insert the tabbed end of the collar from the outside of the hole until the flange butts up tight against the exterior surface of the vessel. Then, from inside, bend the tabs over all the way around the perimeter of the collar as far as they will go. I was able to do the bending with my fingers, no problem.

duct-start-collar-inside.jpg

Here’s what the collar mounting looks like from the inside after, um, about 5 years of use. It ain’t pretty, but you can see how it all goes together and that it’s held up well.


Step 3: Attach ducts

duct-at-D.jpg
duct-at-B.jpg

Put the loose hose clamp around the end of the duct, then put both the duct and the clamp over the protruding section of the start collar. Seat the duct as far down around the collar as you can, then tighten the hose clamp around it with a screwdriver. Don’t overtighten or you risk tearing the duct, which is pretty thin aluminum. Attach one end to the lid (D) and the other to the smoker body (B).


Step 4: Light ‘er up!

smoker_in_operation.jpg

So far we’ve only smoked three things in this rig: salmon, cheese, and sun-dried tomatoes. The salmon was good, and the cheese was better, but the sun-dried tomatoes are unbelievable. They taste like bacon! We start with vacuum-packed sun-dried tomatoes and smoke them for about four hours over mesquite chunks that’ve been soaked in water overnight. I try to keep the smoke temperature, at the food, at about 150F.


Notes and ideas

nummy_tomatoes.jpg

All we’re really doing here is putting a bit of extra distance between the fire and the food to give the smoke time to cool down before it does any cooking. There’s a bit of an art to maintaining a steady temperature; it’s easy to get things hot and not so easy to cool them back down, but it’s not as if the system is terribly complex. If your smoke is consistently hotter than you like, splice in a longer duct and/or try cooling the duct while the smoker is in operation with moving air or even water. It would be straightforward to knock together a digital temperature controller for the thing, at least from the electronics end.

16 thoughts on “Make: Projects – Hot to cold smoker conversion

  1. While it sounds odd, I’ve had truffle infused honey, which was startlingly good as an accompaniment to various cheeses. I’d bet you could smoke honey and get much the same effect.

  2. The start collars look like they are made of galvanized steel, which may be unsafe to cook with. It is unsafe to cook with galvanized steel in contact with the food, it may also be unsafe to cook with galvanized steel in the heat source. Cooking with galvanized steel in the heat source may cause “Metal Fume Fever”, cooking with galvanized steel in contact with the food will cause “Heavy Metal Poisoning”. Please be careful and do research before choosing a metal to use for cooking.

  3. Galvanized steel is coated with metallic zinc.

    “Metal fume fever” is caused by inhalation of zinc oxide smoke. Three points:

    First, zinc oxide is only toxic by inhalation. It is used the world over as a sunblock and is, in fact, commonly *added* to foods and to mineral supplements as a source of dietary zinc. So even if large quantities of it were deposited in the food it would be completely harmless.

    Secondly, it is unlikely that the smoker is going to get hot enough (480C) to cause metallic zinc to oxidize at an appreciable rate.

    Thirdly, even if large volumes of zinc oxide were being produced, this is a smoker, after all, and no one is going to be standing over it trying to breathe in the smoke.

    Now, as to the question of metallic zinc. Metallic zinc is quite benign as metals go, and although large amounts of it can be toxic, it is extremely unlikely that even small amounts of it are going to get on the food in this arrangement. Two points here:

    First, the galvanized steel does not come into direct contact with the food, or even come close to the food, so there’s no opportunity for direct physical transfer of metallic zinc.

    Second, zinc does not begin to vaporize until 1600 degrees Farenheit. There is simply no way, even at hot smoking temperatures, that metallic zinc is going to transfer to the food by vapor deposition.

    Please be careful and do some research before trying to frighten people.

  4. Very “cool” idea!

    How long does it take to smoke something like cheese? Do you take just a brick or wedge and use it as is or does it work better to cut it into smaller blocks?

    My grandfather used to smoke chickens – if doing meat this way does it need to be par cooked before or does the smoking take care of any bacterial concerns?

    Thanks for a do-able build!

    1. More surface area is better for smoking anything, so yeah, cut cheese into smaller chunks for smoking.

      I hesitate to give advice about meat, and I would be especially leery of chicken. Just maybe if I had raised, fed, and butchered a chicken myself I might be personally willing to just smoke and eat it, but I don’t think I’d ever risk it with a store-bought bird.

      1. Cold smoking is the traditional method of making bacon. I am surprised you have not done this and highly recommend it.

        The process is simple:

        1) Get a pork belly and remove any huge chunks of excess fat
        2) Cure pork belly with salt and whatever else you like for 24 hours (Traditionally this will include molasses, brown sugar or maple syrup)
        3) Smoke the belly for about 3 hours at around 200F. You want the final internal temp to be 150F.

        Tada… you now have bacon. Note that your bacon has no sodium nitrate in it, this means it may not be a pretty bright pink and it will not keep for a thousand years. However, it will be the best bacon you have ever tasted.

        A typical pork belly is 5 pounds so you may want to consider freezing some of the bacon. If you do this, slice it first and keep the slices separated with plastic/parchment.

        I don’t suggest cold smoking poultry. Smoked chicken is amazing but you want the smoking chamber to be around 250-275 and the cooking time to be 2 hours at most. The internal temp should be 165 when done and the meat will coast to 170.

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I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and makezine.com. My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

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