I recently built a temperature control unit for cooking sous vide. For those unfamiliar with sous vide, it is characterized by cooking food in a vacuum sealed bag for (usually) relatively long periods of time in a temperature controlled bath. An excellent and beautiful book on this is Thomas Keller's Under Pressure.
For details on the construction process, I generally followed the instructions for a temperature controller that enthusiasts have made to control the smoking temperatures for smoking food. The only difference is that I purchased this PID temperature controller from Auber Instruments, as well as an immersible probe accurate to 0.1 °C. I also added a power switch and a fuse to protect the PID controller. Total cost of this project was $110 including taxes and shipping. This is dirt cheap compared to the $450 Sous Vide Supreme or any of the medical grade immersion circulators.
Once the temperature controller is setup, it's as simple as plugging it in and connecting it to a rice cooker, slow cooker, or in my case, a 1300W electric burner. I found that it kept a stock pot at a pretty stable temperature (generally within .2 °C of the target).
I've read about and heard about sous vide short ribs and wanted to try it out. After reading Under Pressure and some other online sources, I decided on 57.2 °C for 48 hours. The temperature would give me medium rare doneness, and the long cooking time would make sure the connective tissues had time to dissolve and become tender.
Since I don't have a real vacuum packer, I used ziplock bags and a straw to suck the air out. Ghetto, yes, but does the job. Sort of. I packed three different bags: 1) plain salt and pepper, 2) salt, pepper, and a sprig of thyme, and 3) salt, pepper, and about 1/2 cup beef stock. The third option would be the closest to a traditional braise. The beef I used was from Morris Grassfed Beef.
I labeled the bags, zipped them up, and dropped them into the water. How did it turn out? Tune in next time to find out!