Can't afford a Big Green Egg? You can build a ceramic smoker from a flowerpot in a matter of minutes — Alton Brown showed how on "Good Eats". Here I show how to add temperature control to your flowerpot smoker so that you can "set it and forget it". With automatic heating you can take the fiddling and guesswork out of using your smoker... and still have an excuse to hang out in the garden drinking beer.
To build the basic smoker you will need a large ceramic flower pot, the largest you can find. The idea of using a flower pot is that the ceramic walls retain moisture as well as heat — which is ideal for slow cooking. You will need a lid for the smoker too: a matching base will do fine, but a ceramic bowl of the right width or duplicate flowerpot turned upside down will allow taller objects on the grate. Prop the flower pot on ceramic feet or otherwise arrange it so that air can come up through the drain hole. Then take a single ring electric burner. Remove the element from its casing and reconnect the spade connectors directly to the electric cord, bypassing the temperature dial. Put the burner in the bottom of the flower pot and feed the cord out of the drain hole. You may need to lay the element on a brick to get it level. Next put a metal tray of wood chips on the burner. A pie pan will do fine, but avoid anything with a nonstick surface. Finally prop a circular BBQ grate inside the flower pot. Watch this video to see the master at work:
The heating element will be governed by a PID controller that is connected to a solid state relay (SSR). A PT100 temperature probe measures the temperature inside the flowerpot. The controls will fit in a 6" x 6" x 4" PVC junction box if the heatsink for the SSR is mounted on the outside, otherwise a larger box will be needed. The controller box will also need a fuse to protect the controller, on/off switches, and sockets to plug in the burner and the temperature probe. I used separate on and off switches connected via a power relay, but a simple rocker switch will do fine as long as it is rated for 110 V and 15 A. 3 pin XLR connectors are handy to attach the probe using a microphone cable. I recommend protecting the outlet receptacle from the weather with an in-use cover.
To assemble the controller box, use the circuit schematic below (click the picture to make it bigger). If you don't already have them, you will need a soldering iron and a crimper to make the electrical connections and a multimeter to test them. An electric drill will be useful for making holes in the box and attaching screws.
Put damp wood chips in the pan, slap your favorite cut of meat on the grate, and set the required temperature on the controller. Then sit back until the food is ready. A probe thermometer can be used to monitor the internal temperature of the meat.
Perhaps try customizing the smoker to your personal requirements. A simple way to ventilate the smoker is to drill small holes in the lid using a masonry bit and cover them when necessary with with stones. While you're at it, make another hole for the temperature probe. A handle for the lid is a very useful feature. To make a mobile BBQ station, cut a circular hole in a butcher block using a jigsaw or router and mount the flowerpot inside.
Please remember to use mains electricity safely. The controller is designed to provide some protection against the weather, but it is not completely waterproof. Always plug the controller into a GFCI protected receptacle when cooking. Undercooked food can cause illness: calibrate your probe if what you are cooking requires accurate temperature measurement.
This project is one for the Expert. Do not attempt to build the controller unless you can competently wire up mains electricity. The flowerpot smoker itself is easy to assemble but the 110 V supply is potentially Dangerous.