What Is Sous Vide Cooking?

Medically Reviewed by Dany Paul Baby, MD on November 09, 2022
5 min read

Sous vide is a French term that means “under vacuum”. It’s a method of cooking where food is vacuum sealed in a bag and cooked in a temperature-controlled water bath. It’s been used in restaurants since the 1970s. In recent years, sous vide equipment for home kitchens has become more widely available and affordable.

The sous vide cooking process starts with sealing raw or partially cooked foods in a food-safe plastic bag. The bag is placed in a water bath that’s heated between 65 to 95 degrees Celsius (149 to 203 degrees Fahrenheit). 

As the water is constantly circulating in the water bath, there are no cold or hot spots. The food cooks precisely to the temperature that the water is set at.

Many different types of food can be cooked sous vide. Sous vide examples include:

  • Steak
  • Pork chops
  • Eggs
  • Different types of vegetables
  • Legumes and cereals

Professional kitchens use a dedicated machine for sous vide cooking, but home cooks can easily sous vide at home with an immersion circulator. This is a stick-like device that you can clip onto the side of a pot of water. You just need to set the temperature, and the device will heat and maintain the water at that temperature.

If you don’t have sous vide devices at home, you may also use a slower cooker, rice cooker, or convection steam oven to cook sous vide. A convection steam oven may need to be monitored more closely because it’s less precise than a sous vide machine.

According to research, sous vide cooking benefits include:

Consistency. During sous vide cooking, the food is cooked to a precise temperature. For example, if you set your sous vide device at 140 degrees Fahrenheit, the water is kept at this temperature. Sous vide machines generally have temperature swings of less than 0.2 degrees Fahrenheit (0.1 degrees Celsius). This makes it impossible to overcook the food, and also gives you greater control over the doneness of your food.

Tenderness. Tenderness is especially important when it comes to cooking meat. The most expensive cut of beef is the tenderloin, which is also the most tender.

When meat cooks at temperatures above 140 to 150 degrees Fahrenheit (60 to 65 degrees Celsius), the muscle fibers shrink and lose a lot of water. This results in meat that is tough and hard to chew. Meat that’s been sealed in a pouch and then cooked has far less shrinkage and loss of moisture, so it’s more tender. Scientists also say that as meat today is leaner than before, traditional cooking methods may result in food that is dry and tough.

Some foods, like cuttlefish, are tenderized before cooking, as it will get rubbery when cooked. When cuttlefish is cooked sous vide, the low temperatures stop the meat from shrinking and result in more tender cuttlefish. 

Nutritional value. When you boil or steam vegetables, the heat damages their cell walls, and the nutrients leach out. Vegetables that are cooked with the sous vide cooking process keep almost all their nutrients because their cell walls are kept mostly intact. Sous vide also intensifies the flavor of vegetables.

Convenience. Sous vide cooking also offers convenience, both for the food industry and the home cook. Once the food is cooked thoroughly via sous vide, it can be kept in a hot water bath for up to two hours before serving. You can also cook food using sous vide more than two weeks in advance, then store it in the fridge. This won’t affect its freshness or flavor. This is especially useful if you have large batches of food to cook.

Besides its convenience and consistency, the sous vide cooking process also has health benefits, including: 

Use less fat and salt. When you cook sous vide, all of the juices and flavors of the foods remain in the vacuum-sealed pouch. The resulting flavors are more intense, which means that you don't need to add much salt to your food. Also, as the food is cooked in a water bath, you don’t need to add fat before vacuum sealing it.

More nutritious. Researchers say that food cooked sous vide holds more nutrients than food cooked using traditional methods. In a study of cereals and legumes, those cooked sous vide had a significant increase in minerals like iron, copper, magnesium, zinc, and potassium compared to traditional cooking methods. The cereals and legumes studied include peas, red lentils, and pearl barley.

Similarly, a study found that vegetables cooked sous vide had higher amounts of plant compounds, like Vitamin C (ascorbic acid) and carotenoids, compared to those cooked traditionally, such as steaming or boiling. 

Healthier than other cooking methods. When you cook foods using high-temperature cooking methods, like frying and grilling, potentially harmful substances like polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs) may form. Scientists say that these substances may cause changes in your DNA that may increase your cancer risk.

If you follow good food safety practices, sous vide risks are low. But because harmful bacteria that cause spoilage and food-borne illnesses can be found in raw foods, they must be cooked to certain temperatures and for adequate time to kill the bacteria.

These bacteria grow most quickly between temperatures of 40 to 140 degrees Fahrenheit (8 to 60 degrees Celsius). This is known as the “danger zone”.

Sous vide cooking is done at temperatures that overlap this “danger zone”. So to kill the bacteria, food must be cooked sous vide for longer periods. For example, scientists say that sous vide cooking chicken breasts at 140 degrees Fahrenheit for 1 to 4 hours (depending on their thickness) is as safe as cooking it to 165 degrees Fahrenheit using regular methods.

If you’re not eating sous vide food immediately, cool it quickly in an ice water bath then place it in your fridge or freezer. When you’re ready to eat the food, thaw the food in the fridge. Don’t leave any food out at room temperature for more than two hours.

Sous vide cooking should be done with food-safe bags that are meant for sous vide. These bags are typically made of inert polyethylene, and are free of potentially harmful chemicals like phthalates and bisphenol A (BPA).

When your food is in the water bath, check that the bags are sealed properly. Leaking or punctured bags may lead to contaminated or spoiled foods.