Sous-vide is a method of cooking in which food is placed in a plastic pouch or a glass jar and then placed in a water bath or steam environment for longer than normal cooking times (usually 1 to 7 hours, up to 48 or more in some cases) at an accurately regulated temperature. The temperature is much lower than normally used for cooking, typically around 55 to 60 °C (131 to 140 °F) for meat, higher for vegetables. The intent is to cook the item evenly, ensuring that the inside is properly cooked without overcooking the outside, and to retain moisture.
The sous-vide method is used in many high-end gourmet restaurants by chefs such as Heston Blumenthal, Paul Bocuse, Michael Carlson,Thomas Keller, Grant Achatz, Ferran Adrià, Joël Robuchon, Philippe Rochat, Alessandro Stratta, Charlie Trotter, Michael Mina and Joan Roca. Amtrak also uses this method for meals served on their trains, including the Acela Express.
Sous-vide has become common on cooking TV shows such as Iron Chef America and Top Chef, and even in restaurants such as Panera. It has also been used to quickly produce significant quantities of meals for hurricane evacuees. Non-professional cooks are also beginning to use sous-vide cooking.Initially, enthusiasts used laboratory-grade thermal immersion circulators, often bought used on eBay, which required very careful cleaning and, even then, were not recommended for kitchen use. Beginning in 2008, Auber Instruments and Fresh Meals Solutions made available comparatively inexpensive yet highly accurate PID controllers with attached thermocouple probes that could be used to control commercial rice cookers, slow cookers, electric stock pots, and similar apparatuses. In late 2009, several machines intended for home use and less expensive than laboratory-standard equipment went on sale.
More expensive but more universally usable solutions are available in the form of combi steamers, which combine convection and steam cooking methods into a single device. Instead of water baths, they feature tightly-controlled steam generation systems (not requiring the use of a sealed bag). It is possible to duplicate some effects of sous-vide techniques through the use of a beer cooler filled with warm water, checked with an accurate thermometer, and resealable bags with the air removed to package the food for cooking. However, the heat loss involved in this technique makes it unfeasible for long-term (four-plus hours) cooking.
Sous vide, French for "under vacuum," implies that food should be sealed in a plastic bag with all the air removed. An alternative method is to place the food in an open-sided plastic bag and partially submerge the bag into the water, forcing out the air. This method involves clipping the open side of the bag to the side of the pot to keep water from leaking into the opening. The goal is to have the food completely in contact with the hot water to assure even cooking while reducing off-flavors from oxidation.
Lower-cost units are now available in the form of a stick which has a clip to attach it to the side of the cooking vessel. Sous Vide sticks provide a heating element, controller, and motorized impeller. They are available online for $56 or more with the higher-cost units providing a higher degree of control over the water temperature. Devices are becoming more user-friendly, with apps affiliated with most of the devices, including brands such as Nomiku, Anova Culinary, and Joule. Apps guide people throughout the steps of cooking, with some units having voice-control integration. They are connected to WiFi to control the device remotely.