[pdc56]

I second this. Precise temperature (with good conduction between the heat source and the food) and time.

I've cooked 'sous vide' under a running hot tap in a backpacker, which worked great. The water temp happened to be close to perfect (I have a method of measuring temperatures > 40c based on how long I can hold my hand under the running water before pulling out from the pain - surprisingly accurate).