At any rate, one show last night (Tuesday June 8 2010) included a segment whereby three people made smokers from new galvanized garbage/trash cans. At first I was concerned because several years ago I was making a smoker that had an exhaust pipe that included a galvanized pipe, and the research I did said that, if the temperature gets hot enough, then the galvanized material would burn off, and that the chemicals released could be destructive to our nervous system. However, they are only cooking below 300 degrees, and there is no direct contact with the walls of the cans by anything hot (no charcoal or fire), so the walls never get exposed to temperatures higher then 300 degrees, which is below the point where I've seen the galvanized material released, so in my non-expert opinion, I don't think this is a problem for me. If you consider making one of these, you should research this question for yourself in order to decide if you think this is something you feel safe with.
The setup is very similar to Alton Brown's (FoodNetwork) clay flower-pot smoker: it contains a hotplate resting on the inside-bottom of the can, then a small oven-pan on the hotplate, and wood chips in the oven-pan. Up at the top of the can, three small 'L' bracket supports (metal, about 1-2 inches to a side) are each placed evenly around the insides of the can (e.g., 12 o'clock, 4 o'clock, 8 o'clock). These 'L' bracket supports provide the support for the grill surface (the type found on a standard charcoal grill). If you were looking from the side, then the bracket would be positioned something like the an inverted 'L' - the horizontal part is at the top, and the vertical part is below. This allows the grill to reset on the 'L' bracket, without the vertical part getting in the way of the grill surface.
Measure the inside of the new trash can so you can determine the right grill surface to purchase. Home Depot sells different sizes, or you can order online. You will want a grill surface that is low enough so the meat you are smoking will sit on the grill surface, but the meat not extend up as high as the top (lip) of the can with the lid removed. When using the smoker, you will be placing the lid onto the can, and you don't want the meat to come in contact with the lid.
The 'L' brackets you use should have pre-drilled holes in it to simplify mounting the 'L' bracket to the can interior. Determine the height you want for the grill surface on the interior wall of the can, then measure this point down from the lip - this will be your reference measurement. All 3 'L' bracket holes should be drilled into the can wall at the same height from the top of the can, so the top part of the 'L' brackets will provide a uniform level height for the grill surface to rest on. So the holes are all at the same height from the top of the can, the 'L' brackets are attached to the can side wall, the tops of the 'L' brackets are all at the same height from the top of the can, the grill rests on top of the 'L' brackets, the meat rests on top of the grill surface, and the top of the meat is below the top of the can, and the lid will rest on top of the can without touching the lid.
The electrical cord can either come in from the top, or a hole can be drilled in the side wall of the can, a couple of inches below the bottom of the can - it should be above the bottom but below the top of the hotplate. The side entry is the method I prefer, but if you use this approach, then you will need to protect the hotplate wire from direct contact with the hole side, else the trash can will eventually cut through the insulation, which could cause the trash can to become an electrical and fire hazard to you and your surroundings. A rubber grommet that is placed into the hole side will prevent this, or some other type of non-metal short pipe can help with this. Only use this type of smoker on an electrical outlet that has is on a GFI (ground fault interrupter) to provide some additional safety. For me, I would never bring the wire in from the top.
They didn't show a thermometer on the show, but I would recommend placing one in the side of the can, where it can be viewed on the outside without having to take the lid off. It should be at the same hight above the grill surface as 1/2 the meat you will generally be smoking. For instance, if you are smoking a pork shoulder, and assuming most of those are about 8 inches thick, then 1/2 of the 8 inches would be 4 inches, so you would drill the hole for the thermometer 4 inches up from the grill surface. DO NOT USE A MERCURY THERMOMETER! Use a dial thermometer, with a shaft of about 3 - 4 inches long, so it will project into the area above the grill surface.
The hotplate you use should have an adjustable temperature control on it. You will have to experiment with this adjustment in order to find a temperature that provides you with the correct amount of heat. This will be a slow process to find the correct setting!
Determining the setpoint value for the temperature knob:
- Turn the hotplate on.
- Place the lid on top of the can
- If the temperature stabilizes below your desired temperature (more on this later), then take the lid off and adjust the temperature control knob for higher heat, close the lid and wait. This could take 20 minutes.
- If the temperature rises above your desired temperature, then take the lid off and adjust the temperature control knob for lower heat, close the lid and wait. This could take 20 minutes
- Continue with steps 3 and 4 until the temperature matches your desired value.
- Larger cans require bigger hot plates and more energy to heat to your desired temperature. The highest temperature possible in a large can will be lower then the highest temperature possible in a small can.
- Smaller cans will come to desired temperature quicker.
- Smaller cans will mean flare-ups can become self inducing and cause the temperature to greatly increase, while larger cans will be less affected by this.
- The amount of wood chips will determine the amount of smoke flavor. This is more important at the start then later on. The pan containing the wood chips should be directly on the hotplate. Smaller, thinner wood chips will work better then big chunks, but big chunks will last longer, so you might want to try some of both and experiment. If you have trouble getting the chips to smoke, try a smaller and/or thinner pan. If that still fails, you may need a hotter (more watts) hotplate.
- BBQ is generally cooked at or below 250 degrees. The lower the temperature, the longer it will take to cook the meat, but the meat will contain more moisture. Some smoke their BBQ for 20 - 24 hours at 180 degrees. If you are inexperienced, then a good target to start with is 225.
- You will not be able to sear the sides of the meat in this smoker, so if you desire this, you will have to do it inside on your stove in a pan.
- I don't generally test for how done it is, because I feel that, if I can pull it apart without resistance, then it cooked for long enough and reached a high enough temperature for me. I would recommend the use of a meat thermometer, and obtain proper pork temperatures from the pork association web site. Older cookbooks will contain temperatures that are too high and will result in dried out meat, so you should get the latest from the pork association.
- Generally, this should be considered indirect heat, unless you have the grill surface very close to the hotplate and wood chips, and it is prone to self-sustaining flareups.
- On the show, they show the lid opened slightly on one side to let the smoke out. This also lets heat out and fresh air in, which will drop the temperature, which will cause the hotplate to come on, heating the wood chips more, and new fresh smoke. Keeping the can lid on will mean the temperature stays more uniform, the hotplate won't cycle so much, and once the oxygen is used up by the wood chips, the wood chips won't smoke anymore, since they need oxygen to smoke. However, since the smoke is trapped in the can when the lid is on tight, I don't know that this matters. So experiment!
- Per The Other White Meat site (below), a note on temperature (Note: this information may no longer be current so check directly with their site for the latest temperature recommendations): Pork today is very lean and shouldn’t be overcooked. The best test of doneness is to use an instant-read meat thermometer to check the internal temperature of your pork. We recommend cooking pork chops, roasts and tenderloins to 160 degrees F., which leaves the center pink and juicy.* Less tender cuts, like pork shoulder (butt) and ribs can be cooked long and slow, to render them tender. * For larger cuts of pork, such as roasts, cook to 150° F; remove from the oven or grill and allow to set for 10 minutes before slicing. The temperature of the roast will continue to rise to 160° and the pork juices will redistribute throughout the roast before slicing. If marked above by **, the cut should be cooked until tender.
Some useful links
- http://www.theotherwhitemeat.com/Resources/Images/2924.pdf Gives some temperatures to cook at, time to cook estimates and meat temperature. Other useful information at this site as well.
- http://www.altonbrown.com Alton Brown's site.
- A link I found where a trash can smoker was built: http://www.cruftbox.com/cruft/docs/elecsmoker.html