SOUS VIDE COOKING METHOD...

Sous vide is  French style of cooking developed by George Pralus in the 1970s.
The term pronounced "sue veed” means to cook”"under vacuum.".  Sous vide is a method of slow cooking food in vacuum sealed  bags placed in warm water at low temperature.  Foods cooked  in the sous vide style tend to retain the shape and
flavor of the foods . The food is cooked in slow cookers in the absence of oxygen and at less than boiling water temperatures used.  Sous vide, the low temperature cooking is a process of cooking food at a very tightly controlled temperature that is  the
temperature at which  the food is served .

History:
 Sous vide was first used in kitchens in France in the 1970s, it is traditionally  the process of cooking vacuum sealed  food in a  low temperature water bath.
This  method was developed by Georges Pralus in the mid-1970s of France who was looking  for a  new  way  of  cooking.

Sous vide cooking time is affected by three factors:
(1) the core temperature  to cook the dish.
 (2) the heat transfer in the food. 
(3) how much food will be cooked at one time.

For example: Meats – which do not conduct heat  well so will require longer cooking times than foods such as vegetables which are much less dense and have greater  surface areas.
 Also, the greater the cooking liquid to food ratio, the faster each portion of food will reach the proper core temperature. The sous cooking involves pressure, temperature and time.
The high pressure is due to the vacuum to lock the heat, temperature is low so that the packing does not tear and the time taken to cook by this method is more.
The ‘art’ of sous vide cooking is  determining the perfect ‘core’ temperature you  need to reach to  get the desired taste and texture.