Sous-vide, French for “under vacuum”, is a method of cooking food sealed in airtight plastic bags in a water bath for a long time—72 hours is not unusual—at an accurately determined temperature much lower than normally used for cooking, typically around 60 °C or 140 °F. The intention is to maintain the integrity of ingredients and achieve very precise control of cooking.
By cooking the food at a precise temperature, foods are cooked to perfection every time. You may decide that the ideal temperature for the interior of a cut of beef is 140 degrees, but by using any traditional cooking method, no matter how good the chef is, it’s pretty hard to hit that number exactly right every time, and there can sometimes by some considerable difference between the ideal and the reality. With sous vide cooking, a food wanted at 140 degrees, will be cooked at 140 degrees in simmering water, and because the cooking medium is not hotter than the desired temperature, the food can never be overcooked, no mater how long it’s left in.
The second reason that chefs love this is for the intensity of flavoring possible. The food effectively cooks in its marinade, and since it’s vacuum sealed into the meat, the effects of the seasoning are more pronounced. Additionally, because the food is cooked under a vacuum, the natural juices are unable to escape from the meat, and the resulting food is much more succulent.
Thirdly, the technique allows for a manipulation of food that is not really possible in any other way. Take short oxtail for example. A really delicious and flavorful cut of meat…but also very chewy, and as such the only way to cook it and make it tender is to braise it low and slow, and keep cooking it until it is thoroughly well done, and all of the collagen in the meat is transformed to gelatin. Trying to eat a medium ox cheek cooked conventionally would be close to impossible. But using sous vide, the ox cheek can be cooked over a very low heat for many many hours, and during this very long and slow cooking, the collagen eventually transforms to gelatin, and what you get is the texture of a sirloin steak, and the incomparable beefy flavor of ox cheek. Pretty remarkable stuff.
Cooking at lower temperatures for extended periods of time also has these benefits:
- Minimal loss of moisture and weight
- Preservation of flavour and aroma as water soluble substances – especially aromatics – are not lost
- Flavours are enhanced, colours retained and little or no salt is required
- Nutrients are preserved as water-soluble minerals are not leached into cooking water, as cooking in a vacuum bag eliminates this
- Research has shown that sous vide gives the highest retention of vitamins vs. steaming and boiling
- Little additional fat is required during cooking
- Consistent results every time a dish is cooked
Professionals cook vacuum sealed food in water baths originally designed for laboratory usage, and these water baths can maintain the precise temperatures wanted for as long as needed.
The vacuum sealed meats can also be held without spoilage for far longer than usual, which is another thing that restaurants love, but this does raise some concerns of botulism.