This special technique does not boil water because the cookers are designed to maintain temperatures within the range of 120⁰Fahrenheit and 180⁰ Fahrenheit. This temperature range is what is needed to prepare various kinds of foods. If you use a conventional, homemade sous vide setup, the temperature can be maintained by pacing the pot on a hotplate with a set temperature. The water will only heat up to the set mark and will not start bubbling.