Sous vide cooking using thermal immersion circulator machines. The intent is to cook the item evenly, ensuring that the inside is properly cooked sous vide bottom round steak recipe overcooking the outside, and to retain moisture.

Low-temperature cooking was first described by Benjamin Thompson, Count Rumford in 1799. He used air as the heat-transfer medium in his experiments while attempting to see if he could roast meat in a machine which he had created to dry potatoes. Preparation of food under pressure, with or without heat, was developed by American and French engineers in the mid-1960s as an industrial food preservation method. As with Rumford, the researchers learned that the food showed distinctive improvements in flavor and texture. As this method was pioneered, applying pressure to food through vacuum sealing was sometimes called “cryovacking”.

The pressure notably concentrated the flavors of fruits, even without cooking. 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, the French chief scientist of Sterling, Virginia-based food manufacturer Cuisine Solutions. Goussault and Pralus independently worked on development of sous vide in the 1970s and eventually became collaborators. Goussault pioneered the marriage of vacuum sealing with low-temperature cooking.

Pralus, considered the father of modern sous vide, cooked at higher temperatures. A steak being prepared sous vide. Sealing the food in sturdy plastic bags retains juices and aroma that otherwise would be lost in the process. Placing the packaged food in a water bath, with the temperature set at the desired final cooking temperature of the food, prevents overcooking, because the food cannot get hotter than the bath it is in, as in bain-marie.

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 and very thick items, given enough time. By contrast, 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, and it must be removed from the high heat prior to 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 undercooked. The use of temperatures much lower than those used for conventional cooking is an essential feature of sous vide. When cooking meat, tough collagen in connective tissue can be denatured into gelatin, without heating the meat’s proteins high enough that they denature to a degree that the texture toughens and moisture is exuded from the meat. In contrast, soft vegetables are often considered overcooked.

Low-temperature cooking allows plant matter to remain more succulent, as the cell walls do not burst. From a culinary viewpoint, the exclusion of air is secondary, but this has practical importance. It allows cooked food to be stored, still sealed and refrigerated, for considerable times, which is especially useful for the catering industry, and it excludes oxygen from food that requires long cooking and is susceptible to oxidation, e. Apart from ensuring uniform cooking, sous vide cooking facilitates development of desired organoleptic flavors and limits off flavors due to oxidation. The degree of accuracy and constancy of cooking temperature required varies with the food cooked. In some cases, it is not critical. Such food can be cooked in a switched-off slow cooker filled with hot water and a thermometer.

For an egg, though, which has proteins that denature at different temperatures, maintaining precise, constant temperature is more critical. Regular cooking times are determined by when the center of the cooked item reaches a few degrees below the targeted temperature. Then heating should be stopped immediately. While the food rests, residual heat will continue to cook it for a while. If the heating continues, the food will be overcooked. The time taken for the center of food to reach the target temperature depends on the initial temperature, the thickness and shape of the food, and the temperature of the bath.