If you are interested in vacuum cooking, which is also known as sous vide, then you are going to need to get a temperature controller. People who know how to sous vide use a temperature controller to make sure that their meals are thoroughly cooked. Sous vide recipes all talk about having to set a certain temperature to make sure that things like flank steak meat, chicken breast, Salmon, egg,... are cooked so it cooked slowly and also any bacteria in it is killed. With sous vide cooking, you want precise temperature control so your meals will come out delicious.