Transcript
FREQUENTLY ASKED QUESTIONS on Sous Vide Cooking Sous Vide™ Professional CONTENT 1. GENERAL QUESTIONS 2. HOW TO COOK SOUS VIDE 3. VACUUM SEALING 4. TIME, TEMPERATURE & PROBING 5. STORING & REHEATING 6. FOOD SAFETY & CLEANING
PolyScience is a leading global producer of laboratory equipment for customers worldwide. Founded in 1963, PolyScience’s core competence is designing and manufacturing extremely precise temperature control solutions. This expertise presented company president Philip Preston, a passionate home chef, with the opportunity to support the first wave of creative chefs re-examining sous vide cooking. Over this time, PolyScience has developed great relationships with many of the world’s best chefs. Next to their creativity, the best ingredients and knowing what customers enjoy, PolyScience culinary technology has become one important element in their kitchens.
1. GENERAL QUESTIONS WHAT IS SOUS VIDE? Sous Vide is a cooking method in which food is vacuum sealed in a plastic pouch and then cooked at a gentle temperature in a precisely controlled water bath. Compared to other cooking methods, it provides more control and allows for perfect, repeatable results every time. It is easy to learn and takes the stress out of cooking, because food can be held at a perfect level of doneness for a much longer time than usual methods allow. Who should invest in a Sous Vide™ Professional? Anyone that likes to take advantage of a cooking system that allows: - Repeatable, perfectly cooked food every time - The stress to be taken out of cooking by eliminating short windows of time for perfect doneness - Meals to be prepared ahead of time and still taste delicious even days later - The production of the most moist and tender texture - Financial savings by making tougher cuts of meat taste like tenderloin - One to cook like chefs in the world’s best restaurants What are the nutritional benefits of sous vide cooking compared to traditional methods? Food cooked sous vide retains as much of the integrity and important nutrients as possible. Since they will not be lost to cooking liquid and the temperature is lower than with usual techniques, more nutrients remain in the food. Fats in meats and fish, which can be easily damaged at high temperatures in the presence of oxygen, remain un-oxidized, intact, and more healthful. What are the convenience benefits of a Sous Vide™ Professional for a home chef? This technique eliminates all stress, time crunch and worries of overcooking because this technique offers a much greater window of time. Practically one can’t overcook. It takes out the guesswork! The perfect control guarantees that results turn out perfect every time. That gives even a less experienced cook a chance to cook a perfect medium-rare steak or delicate fish filet. The Sous Vide™ Professional also allows preparing meals in advance and enjoying home cooked meals, without compromising quality, even on busy days. What is the difference between a Sous Vide™ Professional and a slow cooker? The Sous Vide™ Professional can be used as a slow cooker, but is outperforming any slow cooker in the following areas: o Level of control and temperature precision - food cooks exact and repeatable every time o Flexibility – cook for 2 or for 50 people. The Sous Vide™ Professional clamps to any size of vessel. o Ease of storage and cleaning – the Sous Vide™ Professional is slightly larger than a stick blender and can be stowed in a drawer. To clean the cooking vessel, simply put it in the dish washer. To set up a Sous Vide™ Professional as slow cooker simply insert a stainless steel pan or ceramic container into the water bath that is controlled by the Sous Vide™ Professional.
2. HOW TO COOK SOUS VIDE What are the basic steps to cooking sous vide? 1. Vacuum seal food in food-grade plastic pouches certified as suitable for cooking. 2. Place pouch in water bath that has reached desired temperature and is precisely controlled by a Sous Vide™ Professional. 3. Let food cook for minimum time. Compared to traditional techniques, food can generally stay longer in water bath without overcooking. 4. Remove and serve! Some foods require a quick sear in a hot pan or on a grill to create a browned surface and impart a caramelized flavor. What kind of foods can you cook sous vide? - Any type of delicate or tougher cuts of meats—such as beef, pork, lamb, game, or poultry. A beef tenderloin will turn out perfectly cooked every time. Spare ribs will be so tender and juicy like you’ve never had them before. - Excellent for delicate fish and seafood, ensuring that these delicate foods are not dried out or overcooked. - Almost any vegetable except for greens (broccoli, green beans). Root vegetables and potatoes benefit very much in flavor and consistency with sous vide cooking - Eggs can only be cooked very precise in a sous vide circulating bath. See our temperature reference guide which illustrates the dramatic changes at each degree. Obviously eggs do not have to be vacuum packaged. - Fruits, in particular delicate ones like peaches, apples and pears do not only turn out with the right mouth feel, but taste wonderful when cooked with flavor infusions. - Cook custard-style ice cream base, béarnaise sauce, crème anglaise and custards without worrying about curdles. The Sous Vide™ Professional water bath is excellent to hold these custards and sauces at serving temperature. (see iSi Whip Canister Holder) How do you season food to be cooked? Because food is packaged in food-safe bags and cooks in its own natural flavors, it does not give up aroma and moisture to surrounding liquid or the air. Seasoning will be more efficient and requires less than usual. With herbs we recommend to use only 30% of what you usually would use. Salt and pepper would not be applied much differently than with other methods. It is important to evenly distribute the seasoning in the bag or on the food. Otherwise there will be parts that have more seasoning than others. As an example: if you cook carrots in cumin butter, simply melt the butter and mix in the cumin powder before introducing it into the bag. One big difference to traditional methods is the use of garlic. Garlic added to foods like steak, chicken or fish does not cook in the cooking pouch at these temperatures. The result is a unattractive flavor. To avoid that, we recommend adding garlic after it is sautéed or roasted. Alcohol in wine, beer, liqueurs, or distilled spirits will not evaporate as it does on the stovetop or in the oven and can develop a harsh, unpleasant flavor. We recommend to pre-cook any alcoholbased liquids that are added as flavor when cooking sous vide.
How much food can you cook with a Sous Vide™ Professional? One of the big advantages to a Sous Vide™ Professional is that it clamps to any size container, pot or vessel, from a small stock pot that holds food for 2-4 people, up to the maximum volume with 7.4 gallons (28 Liter). This allows you to cook for more than 50 people, or cook several items at the same time for over 25 people. When you fill the water bath with food, there should always be enough space to allow for circulation of the water! Make sure that you cover the bath with our custom-lids or plastic-wrap for better heat efficiency and avoidance of evaporation. This matters especially with higher temperatures like 185°F/85°C when cooking vegetables. Can you cook an entire meal in a Sous Vide™ Professional? Yes, there are two ways to cook an entire meal: Foods with different foods cook at different temperatures 1. Since food doesn’t overcook when holding at a lower temperature, one simply organizes the sequence from high to low temperatures. For example, first cook carrots and potatoes at 185°F/85°F for 45 minutes, then lower the temperature to 138°F/59°C for medium-rare beef tenderloin. Adding ice cubes helps to speed up the cool-down process. 2. Pre-cook different foods, chill in an ice-bath and store in the refrigerator. Later re-heat all foods at the temperature that you’ve used for the food with the lowest temperature, which would be at 138°F/59°C for example when serving medium-rare meats. One-pot meals and stews 3. A Sous Vide™ Professional can be used like a slow cooker. Simply vacuum seal your stew into a bag or fill into a container that sits in the water bath and will be cooked by the surrounding temperature-controlled liquid. Visit our website for recipes or share any of your recipes via Facebook!
3. VACUUM SEALING What different methods of vacuum sealing exist? External vacuum sealer A vacuum pump device is clamped to the outside of a bag, pulls out as much air as possible and seals the plastic. While these machines are less costly, light and small, and often accomplish a basic result, the performance is not able to remove as much air as a chamber vacuum sealer. They also present a challenge when liquids are in the bag, since the pump will pull any content from the bag that isn’t heavier than the pump can pull. Chamber vacuum sealer A chamber vacuum sealer is a device that creates a low pressure within a chamber before sealing the bag. Equipped with a powerful pump, it can pull up to 99.9% of air from the bag. It is important to understand two additional considerations when working with a vacuum sealer: When using an external vacuum sealer, how can I vacuum seal bags that contain foods with larger amounts of liquid? - Simply put all the ingredients into a large (1 gallon/3.8 liter) sized zip closure freezer bag, remove as much air as possible from the bag and either zip close or use vacuum sealer to seal only without removing air to guarantee a great seal. - Elevate vacuum sealer to a level that makes it hard for the pump to pull up the liquid. This slows the process of rising liquid and allows you to press the seal button before it reaches the seal area. What should you do if a pouch floats? Ideally there is nothing but the thin plastic between the food and the water. That allows for efficient heat transfer and even cooking. Having little air in the bag can be solved by putting some weight on it, like a porcelain plate. If the bag was properly vacuum sealed and did not float at the beginning of the cooking process and all the sudden developed air inside the bag, you should thoroughly check if that food was not contaminated with bacteria and thus has developed into a food safety risk. If the cooking water has taken on color or food aroma, it is an indicator that the bag is not properly sealed and you should discard it. Compression & Infusions Depending on the vacuum level, the food may be compressed and change texture from the compact packaging. When adding liquids, the vacuum sealing process creates a rapid infusion— especially with more porous foods. This can add benefits to flavor and texture, but may not always be a desired result. For example, a delicate fish filet or chicken breast may become very dense in texture. Therefore, the PolyScience® Chamber Vacuum Sealer features customizable vacuum levels.
4. TIME, TEMPERATURE & PROBING Where can I find times and temperatures? PolyScience provides a sous vide cook book with the Sous Vide™ Professional that lists several recipes and a table with time/temperature guidelines for the most commonly sous vide cooked foods. Find a downloadable version on www.sousvideprofessional.com For what time do you cook foods sous vide? With sous vide one has a much greater window of time for the perfect doneness. Time is much less critical since food is not overexposed to heat and thus cannot really overcook in a traditional sense. Cooking times depend on thickness and tenderness of the food. It can range from as little as 20 to 30 minutes (lean fish, foie gras, scrambled eggs) to as long as 72 hours (spare ribs, tough meats). Thickness: How long it takes a given portion of food to come to temperature depends on the thickness of the portion, not the total weight. Cooking time increases exponential to thickness. A 4 inch thick steak needs at least 3 times of cooking time than a 2 inch thick steak Tenderness: Tender or delicate foods (fish, shellfish, foie gras, beef or pork tenderloin, lamb chops) need only to be brought to the desired serving temperature to be delicious and ready to eat. Extended cooking times can result in their becoming overly tender to the point of mushiness. Portioned chicken breasts and tender steaks typically take a minimum of one or two hours, depending on thickness. Tougher foods (roasts, grass fed cuts, game, spare ribs) will be brought to temperature based on the thickness of the portion, but then benefit from slow low cooking for hours to tenderize them. Skirt steaks and top round roasts typically take a minimum of six hours and a maximum of twelve hours. Ribs and briskets cook for twenty-four to forty-eight hours. Tables for time and temperature are available in the PolyScience Sous Vide cook book or the Temperature Reference Guide. (For recipes and downloads visit www.sousvideprofessional.com.) Can you cook steaks to different levels of doneness at the same time? You would not cook them at the same time, but there are simple tricks to prepare different levels of doneness. Method 1: Cook all steaks in the water bath to medium-rare, then, when finishing the steaks in the skillet or on the grill, simply leave the medium steak on for a bit longer. Method 2: Cook the two steaks sequentially – the medium steak in a 140°F/60°C a day or one hour beforehand, then lower the temperature to 138°F/59°C and add the medium rare steak for another hour. Both cook to perfection. The medium steak will not overcook since it is only being held until ready to serve. After the medium-rare steak is cooked to perfection, sear them quickly for flavor and appearance in a hot skillet or on a grill. Is there a way to measure internal temperature of meat as it cooks? Yes. It can be done if you don’t have the PolyScience recipes handy or want to develop your own recipes. The best way is to cut the bag open on the top, measure the temperature and reseal the bag if necessary. Other ways are to apply foam tape on the bag, poke a temperature needle through the bag and measure that way. However, this method cannot be considered as food safe, because it is breaking the seal and very likely leaks water into the bag. We recommend this method only for recipe development but not for food that’s served for consumption.
At what temperature do you cook foods sous vide? Using the sous vide method, a food is cooked precisely and gently at its desired serving temperature. Sous vide cooking temperatures are generally in the range of 115-190F degrees, and always below boiling. The key to successful sous vide cooking is maintaining a consistent water temperature throughout the cooking period. A difference of as little as one degree can change appearance, flavor and texture of some foods. This level of control allows you to repeat over and over the exact same results of your steak, chicken, scallops, or eggs. Quick reference for cooking temperatures of common foods: Meat –120°F/49°C(rare); 134°F/56°C(medium-rare); 140°F/60°C (medium); 150°F/65°C (medium well) Poultry - white meat – 140°F/60°C to 146°F/63°C up to 160°F/71°C as desired Poultry – dark meat – 176°F/80°C Fish – 116°F/47°C (rare); 126°F/52°C (medium-rare); 140°F/60°C (medium) Shellfish – 135°F/56°C to 140°F/60°C Vegetables –185°F/85°C Eggs – 147°F/64°C (soft boiled) to 167°F/75°C (hard boiled) Cakes – 190°F/88°C Custard – 170°F/76.5°C Tables for time and temperature are available in the PolyScience Sous Vide cook book or the Temperature Reference Guide. (For recipes and downloads visit www.sousvideprofessional.com.) Can I cook slow cooker recipes with the Sous Vide™ Professional? Yes, every slow cooker recipe will work and turn out even more delicious and cooked perfectly according to your set temperature. For well done foods, simply cook all ingredients together at 185°F/ 85°C. For medium-rare or medium foods, lightly sauté or steam vegetables in the skillet and then add them to the meat and spices and cook in vessel or food-safe pouch. How do I set up the Sous Vide™ Professional as a slow cooker? To cook the recipe in a Sous Vide™ Professional, you can: 1. Use food-grade zip closure pouches: Remove air and zip closed 2. Vacuum seal food 3. Fill food into stainless steel or ceramic cooking vessel that will fit into the water bath, controlled by the Sous Vide™ Professional.
5. FOOD SAFETY & CLEANING Food Safety: Is cooking in plastic bags safe? The chief concerns raised about cooking in plastic bags involve the leaching of potentially harmful chemicals, such as BPA (bisphenol-A) and phthalates, or toxic metals, such as lead, from the bag into the food. Food grade plastic bags, certified as suitable for cooking by their manufacturer, are safe to use. Vacuum & Food Safety Vacuum-packaging creates an anaerobic or low-oxygen environment that can encourage the growth of bacteria such as salmonella and botulism when food is handled improperly. Safe food handling and hygiene standards should always be maintained. Food Safety: What clean up is involved when cooking with the Sous Vide™ Professional? Clean up couldn’t be easier. Since the food is sealed in cooking pouches, the water and bath stay clean. Simply recycle the cooking pouch. As to cleaning the vessel after cooking, turn off and unplug the Sous Vide™ Professional, detach it from vessel, wipe dry with a towel and store in a safe place. Clean out vessel in dish washer or sink. Occasionally or when a cooking pouch may have leaked, simply replace the water with a vinegar/water solution and run unit at 160°F for 25 minutes to remove any residuals or lime. After the cleaning process, turn off and unplug the Sous Vide™ Professional, detach it from vessel, wipe dry with a towel and store in a safe place. Clean out vessel in dish washer or sink. Food Safety: Is cooking at low temperatures safe? Reducing the risk of food-borne illness by cooking food depends not just on temperature, but also on time. The lower the temperature, the longer the time. For instance, Salmonella, a common type of food-borne bacteria, will be killed in 30 seconds at 150°F/65.5°C but it will take 15 minutes to do so at 130°F/54.5°C. Almost all potentially harmful organisms will be killed at 130°F/54.5°C given sufficient time to heat the food completely to that temperature. Since most sous vide cooking is done between 130°F/54.5°C and 195°F/95°C, the food will be safe. The most common exception is fish, which some people prefer to eat rare or medium rare (116°F/46.5°C to 126°F/52°C). In this case, it is important to only buy fish you would be willing to eat raw—in other words, sushi grade ocean fish. Important warning: Individuals who are immuno-compromised for any reason should not eat rare or raw food; they should only eat food cooked at or above 140°F/60°C for a sufficient amount of time to ensure the food is pasteurized. What are important food safety considerations with sous vide cooking? When handling food, whether cooking sous vide or using more traditional techniques, all cooks should familiarize themselves with basic food safety practices: • Only work with fresh food that is thoroughly cleaned • Prevent cross contamination by using separate cutting boards, washing your hands and use separate and clean storage units • Observe recommended cooking temperature and times to avoid bacteria growth • Serve food right away or chill properly in an ice-bath and store immediately in the refrigerator. Find additional food safety and handling tips in the PolyScience cook book or visit http://www.fda.gov/food/foodsafety/default.htm.
6. STORING & REHEATING How long can you keep sous vide cooked foods in the refrigerator safely? Any fresh food that is cooked properly and quick chilled can be kept safely in its pouch in the refrigerator for up to 48 hours. After 48 hours, it depends on what type of food it is. Delicate proteins like fish and seafood should be consumed or frozen after that period. Vegetables and meats that have been cooked for longer than 6 hours at 140°F/60°C can be held for 1 week before they have to be consumed. How do you quick chill sous vide cooked foods? Completely submerge food in its pouch in an ice bath (50/50 ice cubes and water) to allow the temperature to drop quickly through the danger zone (40°F/4°C to 130°F/54°C). How long the food should stay submerged in the ice water should mirror the minimum cooking time for that food, in most cases 30 minutes to 1 hour. Do not place the hot or warm pouches in the refrigerator. They will not cool down quickly enough and will heat up your refrigerator and other foods in it.
Is it possible to reheat or cook frozen foods? Yes. This is very practical for two situations: When cooking with raw frozen ingredients, the cooking time needs to be extended for the time it needs to thaw. That is usually double or longer of the regular cooking time. When reheating previously sous vide cooked and frozen foods, the time in the Sous Vide™ Professional water bath depends only on how quickly the serving temperature is reached. What should not be cooked sous vide? Whole chicken, duck or game hen in one piece. The issue with that for any method is that white and dark meats require different cooking times. For sous vide specifically a whole bird cannot be vacuum sealed without remaining a cavity, resulting in uneven cooking. We recommend to break down the parts and cook legs and thighs separate from breasts. Green vegetables, such as green asparagus, broccoli and spinach. Based on our experience and the feedback of the best chefs in the world, green vegetables don’t benefit from longer and low temperature cooking times. Traditional methods like blanching or sautéing achieve much better results. Hamburgers or any ground meats or fish. From a food safety perspective, we don’t recommend cooking hamburger patties sous vide. Bacteria grow on the surface of ground meats due to its increased surface at a much higher risk for bacterial contamination than portioned meat cuts – unless they are cooked at higher temperatures and for extended time. In that case we’d rather use a traditional grill. How long can I hold foods in the Sous Vide™ Professional? With the Sous Vide™ Professional, food can be held at the desired cooking temperature for much longer than with traditional cooking techniques. However, at some point food will become mushy and overcooked in its texture. To ensure perfect results we recommend the following rules of thumb: - For the best results don’t hold foods longer at cooking temperature for double of their minimum cooking time (see PolyScience temperature reference guide for time and temperatures). - Maximum cooking time is 72 hours.
