Sous-vide

Sous-vide (/suːˈviːd/; French for ‘under vacuum’) is a method of cooking in which food is sealed in a vacuum-sealed plastic pouch then placed in a water bath or in a temperature-controlled steam environment for longer than normal cooking times (usually 1 to 7 hours, up to 48 or more in some select cases) at an accurately regulated temperature much lower than normally used for cooking, typically around 55 to 60 °C (131 to 140 °F) for meat and higher for vegetables. The intent is to cook the item evenly, ensuring that the inside is properly cooked without overcooking the outside, and retain moisture.

The method was first described by Sir Benjamin Thompson, Count Rumford in 1799 (although he used air as the heat transfer medium). It was re-discovered by American and French engineers in the mid-1960s and developed into an industrial food preservation method. The method was adopted by Georges Pralus in 1974 for the Restaurant Troisgros (of Pierre and Michel Troisgros) in Roanne, France. He discovered that when foie gras was cooked in this manner, it kept its original appearance, did not lose excess amounts of fat, and had better texture. Another pioneer in sous-vide is Bruno Goussault, who further researched the effects of temperature on various foods and became well known for training top chefs in the method. As chief scientist of Alexandria, Virginia-based food manufacturer Cuisine Solutions, Goussault developed the parameters of cooking times and temperatures for various foods.

As may also be done in traditional poaching, sealing the food in sturdy plastic bags keeps in juices and aroma that otherwise would be lost in the process.

Placing the food in a water bath, with the temperature having been set at the desired final cooking temperature of the food, avoids overcooking, because the food cannot get hotter than the bath it is in, as in bain-marie. In conventional high-heat cooking, such as oven roasting or grilling, the food is exposed to heat levels that are much higher than the desired internal cooking temperature; the food must be removed from the high heat prior to its reaching the desired cooking temperature. If the food is removed from the heat too late, it becomes overcooked, and if it is removed too early, it is under-cooked. As a result of precise temperature control of the bath and the fact that the bath temperature is the same as the target cooking temperature, very precise control of cooking can be achieved. Additionally, temperature, and thus cooking, can be very even throughout the food in sous-vide cooking, even with irregularly shaped or very thick items, given enough time.

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Wikipedia