Anyone who has spent much time working in a chemistry laboratory has probably shared my idle thought, on returning to their home kitchens, that the traditional technology of cooking is frustratingly imprecise. Though I appreciate the great received traditions of intuitive cooking as much as the next guy, I often wish for a temperature controlled, time-programmable range top—ideally with built-in overhead stirring, a gas-tight cooking vessel, a vacuum pump, and maybe an inert gas line–to repeatably and accurately control the full pressure/temperature/time space of the stuff in the pot.
We’re not there, yet, but the technology is getting cheaper. And the DIY sous-vide experimenters are leading the way, at least as far as home users are concerned.
“Sous-vide” is fashionable French for a method of cooking that involves longer cooking times at lower temperatures and reduced atmospheric pressures. It means, literally, “under vacuum.” Commonly, food is sealed in plastic vacuum bags and cooked at temperatures well below the boiling point of water for dozens of hours, although the particular parameters vary widely with the food to be cooked. The point, really, is that the equipment involved is capable of finer automated control of those parameters than your conventional range, oven, and/or microwave, and the quality and flavor of the natural ingredients can be vastly improved—without sacrificing safety—by using it.
In the title video, which has been wildly popular since we first posted it back in November, Cooking for Geeks author Jeff Potter demonstrates a very simple DIY sous-vide setup using a cheap slow cooker regulated by a low-cost digital temperature controller and thermocouple. Basically, his method involves building a temperature-controlled extension cord. The slow cooker (or whatever you plug into it) will be turned on or off as needed to bring the temperature up to the programmed setting and keep it there. Jeff suggests starting with sous-vide eggs by cooking raw eggs in the shell (which don’t require vacuum-sealing) at 148° F for one hour.
With a bit more time and effort, it’s straightforward to build an all-in-one unit that combines a digital temperature controller, a thermocouple, and a circulating immersion heater, a big advantage of which is that you can attach it to pretty much any cooking vessel you choose. Scott Heimendinger designed, built, and documented a great one for us in MAKE Vol 25, and the build is now featured on Make: Projects.