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DRAFTDRAFT

March 2006

Sous-Vide: An Informational Overview

Sous Vide: An Informational Overview

Images in this document are taken without permission from the internet and the book, Sous-Vide Cuisine, by Joan Roca and Salvador Brugués.

• Overview

• Why are chefs using this?

• Sous-vide equipment

• The sous-vide process

• Other resources

Agenda

What is sous-vide?

• Literally, sous-vide means “under vacuum.” The English usage of “sous-vide” is inconsistent and can be confusing. When chefs refer to sous-vide they often mean the whole range of culinary techniques associated with vacuum bags including storage, cooking, cook/chill and special effects like texture modification. Some chefs use the term only to refer to cooking. Some people refer to vacuum sealing machines as “sous-vide machines.”

• The process consists of placing products into bags, putting those bags under vacuum, sealing them, and further manipulating, processing, or storing them. Traditionally, vacuum packing has been used to enhance the storage of food products. Recently, the unique properties of vacuum bagged foods have led to a sous-vide cooking movement that aims at increasing the quality of food and achieving special culinary effects.

Why do chefs use sous-vide?

• Storage• Organization: Vacuum packed pre-portioned foods are neat, sanitary, and easy to

organize. Retrieving food is easy and food is handled only once.

• Cooking: Vacuum bags are sealed –nothing gets in and nothing gets out. This simple fact provides many advantages. Foods don’t dry out during long cooking times. Volatile flavor components are retained. Flavors are not diluted by the cooking medium and small amounts of flavor products have large impacts on flavor. Moist cooking techniques allow very precise final cooking temperatures to be achieved creating unique texture effects. Extended cooking times allow collagen to break down at temperatures that don’t cause proteins to expel all their moisture. Foods that normally oxidize and turn brown during cooking have their color preserved.

• Texture Modification: Spongy products like fruits can have their textures radically altered through vacuum packaging.

• Infusion and marination: Both processes are enhanced under vacuum.

• Forming: The even pressure exerted by the atmosphere on a vacuum bag can be used to create special formed dishes.

Equipment for sous-vide work

• Vacuum machines• Bag technologies• Cooking equipment

– Combi ovens – Circulators

• Temperature monitoring equipment

Vacuum machines: putting food into vacuum bags

• Commercial machines: These are mainly of the “chamber type.” Food is placed in a bag inside the chamber. The lid is closed and the vacuum pump switched on. The entire chamber is evacuated. After the desired level of vacuum is reached, the bag is sealed with a heat-bar and the vacuum is released. These machines can use any type of heat sealing bag.

• Home machines: These machines typically suck the air out of the bag itself. The pumps in these machines are typically much weaker than those in the commercial types. These machines require special bags with micro-channels to work properly.

• Some links:– Multivac: http://www.multivac.com/ – Minipack http://www.minipack-torre.it/eng/home.htm– Koch Equipment http://www.kochequipment.com/packaging2– Cleveland Equipment http://www.thevacuumsealers.com/– Pac Machinery Group http://www.pacmachinerygroup.com/– Berkel http://berkel.com/packaging/vacuum/– Foodsaver http://foodsaver.jardendirect.com/

Bag technologies differ

• Vacuum Bags: There are many different types of vacuum bags on the market. Bags are are often composed of different types of materials laminated together to provide the exact properties needed for a particular application. Some features to consider:

– Is the bag intended for food?

– Is the bag intended for cooking?

• Some bags are only intended for freezing or storage

– Is the bag a shrink bag?

• Some bags shrink when put into hot water. This allows the chef to maintain the shape of foods better.

• Some links: – Sealed Air (Cryovac): http://www.sealedair.com

– Multivac: http://www.multivac.com

Cooking equipment

• Sous-vide cooking in fine dining establishments often requires very accurate temperature control and very even heat. Regular ovens do a relatively poor job of transferring heat. Hot water and steam provide efficient and even heat but traditional simmering and steaming techniques provide poor temperature control. Two major pieces of equipment address this problem.

Cooking equipment: Combi Ovens

• Combi ovens: These ovens combine convection with steaming capability. Most major commercial oven manufactures now offer combi ovens. Combis are typically more expensive than regular convection ovens. Newer combi ovens are often microprocessor controlled, offer the ability to measure food temperature with internal probes, and include very sophisticated recipe programming. Many units have a function for low-temperature steam. Low-temperature steam provides an atmosphere at 100% humidity but at a temperature below 212 F. This is very useful for sous-vide because the temperatures are very even and accurate throughout the oven and heat transfer is very efficient.

• Some links:– Rational: http://www.rationalusa.com

– Electrolux: http://professional.electroluxusa.com

Cooking equipment: immersion circulators

• Immersion circulators: This type of equipment was developed for laboratory use. They are used to heat water to a very precise temperature. Because they agitate the cooking water, the temperature is also very even. Some come with their own water tanks and some have clamps that allow them to be moved from pot to pot. Circulators are very portable and simple to operate. They consist of:

– Temperature controller

– Temperature sensor

– Heater

– Stirring element

• Some links– Polyscience: http://www.polyscience.com

– Haake: http://www.thermo.com/com

– Techne: http://www.techneusa.com

– Lauda: http://www.brinkmann.com/

Temperature monitoring equipment

• Thermometers: In addition to the temperature controls included on cooking equipment, chefs often use thermocouple thermometers to measure the temperatures of foods and cooking media

• Hypodermic probes: These thermocouple probes can pierce vacuum bags without causing leaks. Chefs use these to measure internal food temperature during sous-vide cooking

• Data-loggers: Some thermometers allow chefs to store a log of measured temperatures over time to verify safe temperatures and monitor cooking curves.

• Some links: – http://www.omega.com/temperature/tsc.html

– http://www.microdaq.com/

– http://www.taylorusa.com/foodsvc/thermo/

There are two major sous vide heating processes: cook chill and direct serve

Cook ChillCook Chill

• Food is cooked, chilled, and reheated for service.

• Traditional high-temperature cooking and new lower-temperature cooking can be used.

• The temperature of the cooking water or combi oven is kept at the desired finished internal temperature for the majority of the cooking time.

• This technique is typically used for meats and poultry.

• Food is cooked, chilled, and reheated for service.

• Traditional high-temperature cooking and new lower-temperature cooking can be used.

• The temperature of the cooking water or combi oven is kept at the desired finished internal temperature for the majority of the cooking time.

• This technique is typically used for meats and poultry.

Direct ServeDirect Serve

• Uncooked vacuum packed food is heated and served directly to the customer.

• Usually used with new, lower-temperature cooking techniques.

• The temperature of cooking water is kept roughly 10 degrees F higher than the desired internal temperature.

• Cooking times are typically 8-11 minutes to accommodate restaurant service needs.

• This technique is typically used for fish.

• Uncooked vacuum packed food is heated and served directly to the customer.

• Usually used with new, lower-temperature cooking techniques.

• The temperature of cooking water is kept roughly 10 degrees F higher than the desired internal temperature.

• Cooking times are typically 8-11 minutes to accommodate restaurant service needs.

• This technique is typically used for fish.

Cook chill

• Here is a comparison of meat prepared using cook-chill sous-vide (left), and traditional cooking (right) taken from Sous Vide Cuisine:

• Note that the meat cooked sous-vide has the same level of doneness throughout; while large portions of the traditional steak are overcooked. The sous-vide steak has also retained much more moisture, as can be seen by the shrinkage of the traditional steak. The only disadvantage of the sous-vide method is the paler crust color and the lower level of associated “brown flavors.”

Direct-serve

• Here is a comparison of salmon prepared using direct serve sous-vide (left), and traditional cooking (right) taken from Sous Vide Cuisine:

• Note that the fish cooked sous-vide has the same level of doneness throughout, while large portions of the traditionally cooked salmon are overcooked. The texture of fish cooked sous-vide is something that has to be experienced --It is unlike that of traditionally prepared fish. The sous-vide fish does not have the “brown flavors” associated with many traditional cooking techniques.

Other sous-vide tricks (taken from Sous Vide Cuisine)

• Oxidation: Oxygen-related browning of foods can be prevented under vacuum. The artichokes on the right were cooked sous-vide. Those on the left were cooked traditionally.

• Texture modification: On the left is an image of a dessert made with apple chunks that have been vacuum packed. The packing alters the texture, making them denser.

• Infusion: On the right is an image of crème-anglaise made sous-vide. Not only is the texture perfect because of accurate temperature control, but flavor is infused more effectively

• Forming: The pressure exerted by the atmosphere can be used to form dishes. Here, squid strips are compressed in a vacuum bag, frozen, and sliced to create a decorative effect.

More resources on sous-vide

• Cuisine Solutions: http://www.cuisinesolutions.com Cuisine Solutions is a manufacturer of RTE sous-vide products for foodservice institutions, airlines, restaurants and the like. Their chief scientist, Bruno Goussault is a world authority on the sous-vide process and on sous-vide safety. He has trained many of the top chefs in the United States and Europe.

• Sous-Vide Cuisine by Joan Roca and Salvador Brugués: http://www.vonl.com/CHIPS/sousroca.htm This is the only book available in English that is useful to chefs. Other sous-vide books are aimed at industrial processes and food technologists.