Sous Vide — Cooking Trend du Jour
By Sharon Palmer, RD
Today’s Dietitian
Vol. 8 No. 6 P. 40

It may have taken awhile to catch on, but this vacuum-packed slow-cooking technique is fast gaining a following among elite chefs, despite some safety concerns.

Imagine yourself at an elegant restaurant dining on poached salmon that is nothing like you’ve ever tasted. It is as brilliantly pink as cotton candy yet has a texture so moist and tender it feels like pudding on your tongue.

Chic city eateries are turning out such masterpieces by using the haute cuisine technique sous vide (pronounced soo veed), which means “under vacuum” in French. Celebrity chefs such as Thomas Keller and Charlie Trotter have been making headlines for perfecting the culinary skill in their high-profile restaurants, pushing sous vide to near cultlike status among gourmands across the country. It seems that if you’re anybody in the celebrity food business these days, your bio must boast a venture into sous vide cooking. Starchefs.com called 2005 “the year of cooking sous vide.”

While a handful of celebrated American chefs have been dabbling in sous vide for the past few years, it wasn’t born yesterday. Sous vide originated in France in 1974 when Chef Georges Pralus experimented with sealing foie gras in plastic and cooking it slowly. Long before the birth of Cryovac (an air-sealed food packaging system), cooks have been using everything from plant leaves to pork bellies to encapsulate food while cooking it to lock in flavors and juices. During the past 30 years, sous vide spread throughout Europe, with its primary function in commercial food processing. Even in the United States, sous vide has been alive and well for years in high-volume foodservice operations as a solution to low-labor, high-quality foods. It wasn’t until very recently that it became the muse for American chefs looking for the next culinary “it” movement.

“The United States is at least a decade behind the European system in the technology of sous vide. They were doing it in France in the mid-’80s. By 1999, it was all over Europe,” says Sue Ghazala, BSc, PhD, a faculty member at Memorial University of Newfoundland in St. John’s and author of Sous Vide and Cook-Chill Processing for the Food Industry (Chapman & Hall Food Science Book, 1998). Ghazala has dedicated her career to investigating minimal thermal processing to preserve nutritional and sensory quality, working with food processing clients across North America.

“In the last few years, sous vide has gained a lot of momentum. Many of the top chefs have been using sous vide and it is starting to proliferate,” says Thomas L. Gregg, president of Cuisine Solutions, a food manufacturer headquartered in Alexandria, Va., that has specialized in sous vide processing for the past 17 years. Cuisine Solutions produces more than 2 million portions per month of premium, fully cooked frozen foods.

Why is sous vide becoming the trend du jour in nouveau cuisine? The answer is simple: Chefs have fallen in love with the fruit of their sous vide labors. Sous vide processing produces a food with vivid color that is incredibly delicate, tender, and has an intensely concentrated flavor.

Sous Vide: A Precise Science
Sous vide has been defined as raw material or raw materials with intermediate foods that are cooked under controlled conditions of temperature and time inside heat-stable vacuum pouches. They are kept in chilled storage at 1°C to 4°C (33.8°F to 39.2°F) with a shelf life that ranges from six to 42 days.1 Essentially, raw foods are vacuum-packed in plastic pouches that are simmered in a water bath at lower-than-normal temperatures for longer-than-normal periods of time. A temperature probe inserted into the pouch allows the food temperature to be monitored while it cooks. The traditional method of blasting the outside of a large piece of meat with high temperatures while the core takes its time to rise to the desired temperature is starkly contrasted with sous vide in which the low temperature water bath provides a kinder, gentler method of cooking.

“Basically, sous vide combines science and the art of cooking,” says Gregg, who reports that the method is much more precise than other forms of cooking. In fact, in a 2003 issue of Art Culinaire, Keller hailed sous vide cooking “as precise as a Swiss clockmaker.” By using such constant, low temperatures, chefs can determine the precise scientific moment when a change in the food occurs—from protein coagulating to collagen dissolving.

Ghazala reports that you can follow an infinite combination of time and temperature while processing foods via sous vide. She notes that sous vide cooking is based on the food industry processing principle of cooking at 90°C (194°F) for 10 minutes. For seafood, you might consider a lower temperature such as 70°C (158°F) for a longer period of time to achieve better results. Most processes can be performed in two to three hours, but some chefs process foods for days at low temperatures. “The cooking times remain very flexible, such as cooking duck breast in a 131°F water bath for five to seven hours, and it is still a beautiful medium rare,” says Kevin Miller, a sous vide enthusiast in Stonington, Conn.

“You need to chill the pasteurized product quickly—from 90°C to 28°C [82.4°F] in less than two hours,” says Ghazala, who reports that with new technology in refrigeration systems, this can be achieved easily and quickly. “If you use a household refrigerator, ice, or a freezer, you will not lower the temperature fast enough.”

Some students of sous vide have turned their kitchens into virtual laboratories with commercial-grade vacuum sealing equipment, immersion circulation systems to provide homogenous heat, thermal circulators that control water temperature to a fraction of a degree, and liquid nitrogen cooling systems to quick-chill processed foods. But plenty of sous vide followers rely on a household FoodSaver, simmering pans of water over the stove or in the oven, and the aid of a digital meat thermometer to process food.

Signature Appeal
The vacuum process not only keeps all components of the food intact during the cooking process without exposure to the air to dry up juices, but the pressure of the vacuum also forces added ingredients into the product. Chefs are taking this concept and running with it by creating their own signature sous vide dishes—from truffles infused in veal tenderloin to lobster spiked with fresh ginger and lemon. Some are even doing two-stage sous vide cooking, in which gelatin capsules of delicate ingredients such as truffle oil are inserted, which then burst partway through the cooking process to delay the mixing of fragile ingredients. When the sous vide process is complete, just reheat the meat portion of the pouch, turn the remaining ingredients from the bag into a luscious sauce, and voila—you’ve got an entree worth talking about.

“Some items—such as BBQ, braised meats, and other high-moisture, low-heat method products—come out better with sous vide than traditionally cooked items. The consistency is far superior compared to products cooked by young, inexperienced chefs,” says J. Hugh McEvoy, CRC, CEC, president of Chicago Research Chefs.

The end result of sous vide is vastly different from conventional cooking. For example, sous vide has spawned a new way to boil eggs. Everyone knows what a hard-boiled egg yolk looks like with its chalky consistency. A sous vide egg cooked at 147°F for three hours produces an egg yolk that has a texture similar to jelly with a creamy, rich feel. Doug Flicker, named best local chef of the Twin Cities in 2005, likes to serve a sous vide egg over polenta in his Minneapolis restaurant, Auriga.

And sous vide doesn’t stop there. Chefs rave about what sous vide does for fruits and vegetables, lending a just-picked color and flavor that is so velvety it literally melts in your mouth. The vacuum process allows added ingredients to impregnate the fruits and vegetables with flavor. Just try to resist sous vide apples with water chestnuts pickled with vinegar or root vegetables with chicken stock, olive oil, and fresh herbs.

Sous Vide 101
Serious chefs are traveling to France and England to learn the knack of sous vide cuisine to bring it back home to their upper-crust clientele. These skills are then passed down to staff and spread to new restaurants. Now, culinary arts programs across the country are starting to include sous vide techniques in their curriculum. And for a hefty price, there are a few sous vide experts willing to make a pit stop at your foodservice establishment to set you up.

Many culinary professionals are learning the science of sous vide in bits and pieces—reading about it in books, newspapers, magazines, and blogs or catching a glimpse of it from a traveling chef or on television. McEvoy believes that many chefs practicing sous vide are inappropriately educated. “It takes training and education, which has not been readily available to date. Most chefs have been trained since their teens to cook a certain way and now they are asked to learn a different way,” adds Gregg, who notes that Cuisine Solutions has taken on educating America’s top chefs in the art of sous vide cooking.

Not Always the Solution
For all the hype about sous vide, the final products may be perceived as unsavory with their uniform color and raw appearance. After all, Americans have a long-standing love affair with all that is blackened, grilled, crusted, and crisped. “This isn’t the end-all method. People aren’t going to stop using their ovens and stoves,” says Gregg.

Although sous vide won’t give you a crisp outer surface desired in some dishes, you can use sous vide and then apply another cooking technique, such as deep frying, to get the best of both worlds. Chefs are experimenting with searing meats before, midstream, and after sous vide processing to produce the desired effects. In the end, sous vide cooks claim that you trade the deep-roasted, grilled flavors of conventional cooking for delicate, extraordinary textures and the ability to infuse remarkable flavors into foods.

But sous vide is not for the faint of heart. It is a serious time commitment to supervise a water bath for several hours at a constant temperature. Yet, some find sous vide easier than traditional cooking. Restaurants can purchase large cuts of meat, break them down, and sous vide-process them, then use pouches throughout the week with the appearance of freshly cooked entrees. Cooking can be spread out over the course of the day with quick reheating of products during the dinner rush hour.

So why don’t you see sous vide written all over fashionable dinner menus? Most culinary professionals worry that Americans will liken sous vide to the old “boil-in-a-bag” convention and see it as an inferior product. Instead, they hope customers will fall in love with sous vide without even knowing it. And it’s working. Some chefs say their sous vide products are their best sellers.

Sous Vide Spreads Out
There’s no doubt that sous vide has found a home in upper-echelon dining establishments. Trotter reportedly serves 50% of his menu items with at least one element of sous vide in his popular Chicago eatery. “Chefs on the cutting edge have been cooking sous vide. It is now starting to tip throughout the food industry,” says Gregg, who likens sous vide cooking to the advent of the ATM machine. It took more than 20 years for people to start getting used to ATMs, and now they can’t live without them. Gregg predicts that sous vide cooking will follow the same track. Most fine dining trends eventually trickle down to quick service and fast, casual operations. According to Culinology, Chipotle Mexican Grill cooks all its braised pork via sous vide.

Sous vide has many other applications outside the restaurant. It can be an inexpensive, easy route for many food processors servicing a number of operations. Gregg reports that Cuisine Solutions foods prepared with sous vide techniques are used in foodservice settings such as national restaurant chains, hotels, sports venues, airline foodservices, military foodservice, and retail chains such as Costco and Wegmans. “Chances are you’ve had our food and didn’t know it,” says Gregg. Other processors such as Vie de France have relied on sous vide as well. These days, even foodies are attempting sous vide at home.

Europe has had a lot of practice in sous vide. According to Ghazala, 30% of Marks & Spencer foodservice systems utilize this technology. She also reports that a decade ago, a university in Belgium was perfecting a sous vide/cook-chill system with Hazard Analysis and Critical Control Point (HACCP) applications and control steps throughout every process regulated by a computer system. “It is of a similar nature to an advanced vending snack machine where you simply select the meal in a specific portion size and type of food and when you reach the end of the line, the individual meal is freshly prepared to your personal preferences,” says Ghazala.

McEvoy says, “High-end restaurants and hospital healthcare systems are better able to afford the added processing costs than small mom-and-pop middle-price restaurants.” Ghazala believes hospitals are the perfect controlled environment for making the most of sous vide processing.

Mary Etta Moorachian, PhD, RD, CCP, professor at the College of Culinary Arts at Johnson & Wales University’s Charlotte campus, used sous vide products while working in a healthcare facility in Texas. She says, “The products were costly but as close to fresh made as we could find. We enhanced the value of our dinner meals by having grilled fish, chicken, or beef on a skewer and then served one of their sous vide sauces, such as beurre blanc or a meuniere, that were very good. We only had to snip the vacuum packets, re-therm the sauce to appropriate temperature, and the quality and taste were excellent with an upscale, a la carte presentation.”

Sous vide may be the next wave of healthy convenience foods to hit the retail market. Cuisine Solutions already has branded convenience foods in some retail locations and gourmet outlets such as Hickory Farms that sell sous vide ready-to-eat meals. Gregg reports that sous vide cooking doesn’t rely on additives or preservatives; thus, the food can be nutritious and fit into a number of dietary meal plans. Ghazala adds, “Everyone wants ready-to-eat meals that are high in quality and nutritional value. Sous vide processing is the closest food preparation technique to homemade, freshly prepared meals.”

Questions of Safety
Sous vide safety made headlines in The New York Times on March 15 when the New York City Department of Health and Mental Hygiene ordered chefs to stop using the sous vide process. Bruno Goussault, a sous vide expert from Cuisine Solutions, met with New York health department officials to advise them on the European Union regulations for sous vide in restaurants. Cuisine Solutions advised the health department that the life span for vacuum-sealed, cooked, and chilled fish was seven days and for similarly treated meat was eight to 10 days in the refrigerator. In New York, chefs who want to continue vacuum-sealing food must submit a hazard analysis plan created by a food scientist or technologist for approval, and the health department is expected to issue rules for sous vide processing in restaurants by this summer.

So what is all the fuss over sous vide and food safety? Just the thought of low-temperature cooking and extended shelf life should answer that question. “Food safety in sous vide is a major concern. I would be very nervous eating sous vide at a second-rate restaurant,” says Miller, who prepares, seals, cooks, and serves his sous vide products within two days. Although food processors such as Cuisine Solutions pasteurize their products and follow a carefully executed HACCP plan with controls every step of the way, who knows what can happen behind the closed doors of a restaurant kitchen. Experts agree that there are many misperceptions about sous vide in the culinary field, including the idea that putting a piece of raw meat in a bag and vacuum packing it automatically inhibits the growth of bacteria.

“Safety is very critical in sous vide. Most food pathogens are anaerobes, which means [they do] not need oxygen to survive. By using only a vacuum seal, it allows the food pathogens to survive and make the food unsafe. This confirms the importance of strict processing steps, especially pasteurization and refrigeration—even freezing,” stresses Ghazala.

A recent article in Food Technology reported that some of the chief microbiological concerns associated with sous vide products center around psychotropic (bacteria, yeasts, and molds that grow slowly at refrigeration temperatures but optimally above refrigeration temperatures) and mesophilic pathogens that can grow during extended refrigerator storage or temperature abuse.2 There are three main factors that determine the biological safety of sous vide products: intensity of heat treatment and duration, temperature reached and rapidity of cooling, and controlled chilled storage.1

There is also confusion about how sous vide should be regulated. Should sous vide practiced in an individual restaurant or foodservice establishment be considered food processing or food preparation? The 2005 Food Code issued by Health and Human Services and the FDA calls sous vide cooking a form of reduced oxygen packaging (ROP) and lists the required steps in the process, noting that potentially hazardous foods placed in ROP without regard to microbial growth will increase the risk of foodborne illnesses. Since many products in ROP do not contain preservatives, and thus do not possess any intrinsic inhibitory barriers to microbial growth, temperature is the primary barrier. A temperature of 3.3°C (38°F) or lower must be maintained at all times to prevent growth of microbes. The 2005 Food Code also calls for sous vide operations to destroy all vegetative pathogens through a pasteurization process at a minimum.

“The FDA and USDA take this as [a] traditional food processing technique, even if it is implemented in a restaurant. They do not comprehend the principles behind the process and therefore they failed to revise the regulations in order to follow the European system,” claims Ghazala.

According to the codes of Hygiene of the Advisory Committee on the Microbiological Safety of Food (UK), for cook-chill products with an extended shelf life of more than 10 days and up to 42 days stored at or below 3°C (37.4°F), a heat treatment of 90°C (194°F) for 10 minutes or equivalent and strict chill conditions are required to control Clostridium botulinum risks.1

“When considering sous vide products, the control of time and temperature is critical to prevent the growth of Clostridium botulinum. The food protection manager must carefully monitor the temperature of sous vide products. The ServSafe program outlines information, such as temperature control, for the proper receiving and storage of sous vide products and stresses the importance of proper cooking, holding, and cooling of food all based on the recommendations of the FDA Food Code,” says Kristie A. Grzywinski, MS, CFSP, director of science and regulatory relations, National Restaurant Association Educational Foundation.

And even though food safety experts believe sous vide processing in HACCP- controlled settings may be a solution to avoiding risk of foodborne illness, they have expressed concern over what happens to the products once they leave the processing plant, warning that a public health disaster could result if strict refrigeration standards are not maintained at all points of distribution.

Ghazala monitored the refrigeration temperature of products during ground transportation from New Brunswick to the eastern United States and found that truck drivers often shut down refrigeration systems during breaks, resulting in a rise in temperature of products to 12°C to 15°C (53°F to 59°F). Ghazala notes that even standard display refrigerators in grocery stores with temperatures of up to 12°C (53.6°F) are too high and the product will not have the recommended shelf life. Some sous vide processors have used package time-temperature indicators that automatically recalibrate product expiration limits and warn when holding temperatures have exceeded allowable levels.

On the other hand, sous vide has been done successfully in Europe for decades and the vacuum bag reduces human exposure and contamination. “The severity of food safety concerns has been overblown by the media. Like any other food operation, proper kitchen and manufacturing processes will prevent the potential risks from occurring. The basic rules of food preparation still apply,” says McEvoy, whose company provides sous vide training and services to clients.

“I see no reason why a sous vide product cannot be safe for a minimum shelf life of 60 days if stored at 3.3°C [38°F] and below. However, the standard sous vide pasteurization is designed to have a shelf life of 21 days,” says Ghazala. “I would agree that there is a potential for an outbreak of contamination; however, the risk of this is only when one does not follow the strict protocol involved with the system.” She adds that even with sensitive seafood products, under her processes of time and temperature control in which the product was maintained below 3.3°C, the product was safe for one year, even though the sensory quality had declined.

Though it seems we have much to learn in the burgeoning field of sous vide, one thing is for sure: The technology is out of the bag. Now the challenge will be trying to keep up with it.

— Sharon Palmer, RD, is a contributing editor at Today’s Dietitian and a freelance food and nutrition writer in southern California.

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References
1. Garcia-Linares M, et al. Microbiological and Nutritional Quality of Sous Vide or Traditionally Processed Fish: Influence of Fat Content. 2004;27:371.

2. Marth E. Extended shelf life refrigerated foods: Microbial quality and safety. Food Technology. 1998;52:57-62.

Sous Vide Resource Guide
• Cuisine Solutions, www.cuisinesolutions.com (View the NBC 4 News footage in which star chefs demonstrate their sous vide prowess.)

• National Restaurant Association Educational Foundation, www.nraef.org

• Principles of Modified-Atmosphere and Sous Vide Product Packaging by Jeffrey M. Farber (CRC, 1995)

• Sous Vide and Cook-Chill Processing for the Food Industry by Sue Ghazala (Chapman & Hall Food Science Book, 1998)

• Sous-Vide Cuisine, English Edition by Joan Roca (Montagud Editores)