Do You Need a Vacuum Sealer for Sous-Vide?
Sous-vide is more than just a foodie trend. Sous-vide has been used by professional chefs in restaurants for years to deliver perfectly cooked food, to precisely preferred temperatures, every time.
Unlike traditional cooking methods, where foods are cooked unevenly as heat transfers from outside to inside, sous-vide foods are cooked to the precise degree of doneness, with perfectly even results from edge to edge, with no grey bands or tough edges. Delicate meats like fish maintain their tender flakiness, eggs stay soft and creamy, and steaks remain moist and juicy.
How to Sous-Vide?
With sous-vide, foods are cooked slowly in a water bath, at a precise and consistent low temperature. This method retains moisture throughout the food, without overcooking the exterior. Because the food is in a water bath, it can never get hotter than the water temperature, unlike other cooking methods.
Sealing the foods in a vacuum bag protects the flavors from being diluted by the water, seals in moisture and nutrients, and the pressure of the vacuum concentrates flavors. Vacuum sealing also eliminates the presence of air that would insulate the food from the water temperature, improving the precision of the cooking, and preventing oxidation which causes spoiling. Vacuum sealing also allows for cooked foods to be safely stored for long periods of time without going rancid or introducing unhealthy bacteria.
Do You Need a Vacuum Sealer for Sous-Vide?
The words “sous-vide” are French for “under vacuum,” and vacuum sealing is an important part of the sous-vide process. Excluding air from the bag improves the accuracy and precision of sous-vide cooking, prevents oxidation and discoloration of the food so cooked, and allows the cooked food to be simply and safely stored after cooking. For all serious sous-vide cooking, a vacuum sealer is not simply an accessory – it's essential.
Can You Sous-Vide Without a Vacuum Sealer?
Despite the fact that vacuum sealing is an essential part of sous-vide cooking, there are some foods and sous-vide that do not require it. Here are some sous-vide foods that don't require vacuum sealing:
Custards, pâtés, and yogurts
When you are preparing foods that need to set over a gentle heat, you can use canning jars instead of vacuum sealed bags to allow these delicate foods to cook and set at the same time. Delicate foods that would cook in a water bath can be made sous-vide style in canning jars.
When you “sous-vide” eggs, the eggs are cooked directly in their shells, instead of in a bag. With the sous-vide immersion cooking method, eggs can be perfectly poached or soft boiled and maintain their tender creaminess without overcooking. You can also sous-vide eggs to the precise temperature of 130°F or 54.4°C, which kills any unwanted bacteria without cooking the egg. These sous-vide raw eggs are safer to use in dishes that call for uncooked eggs, like Cesar salad dressing or aioli.
Soups, stocks, and stews are notoriously difficult to seal in a conventional vacuum sealer. For liquid foods, it is best to use a conventional zip-sealed type plastic bag to sous-vide the food. By placing the liquid into a zip-sealed plastic bag, and then placing the bag into your immersion bath, the force of the surrounding water naturally pushes the air out of the top of the plastic food bag. When the liquid inside the bag reaches the level of the zipper, seal the bag to exclude air and immerse it in the sous-vide water.
While many people use zip-style plastic bags and this air displacement method to sous-vide a variety of foods, it is not the best method to get the most flavorful sous-vide meats or vegetables. Also, when using plastic bags not designed for vacuum sealing and sous-vide cooking, there are a few additional things to keep in mind.
Food Safety and Sous-vide Cooking
There are a few food safety issues to be aware of when you are getting started with sous-vide cooking, especially if you are not using a vacuum sealer. Here are of the concerns to be aware of:
Dangers from heating plastics
Numerous studies have shown that some low-grade plastic compounds can leach plasticizing chemicals into fatty foods when heated. Plastic bags made for vacuum sealing and sous-vide cooking are made of food-safe polyethelene and polypropylene, but not all plastic bags you may find in your kitchen are safe for cooking in. If you are using a different kind of bag, choose a high-quality, food safe zip-style bag instead.
Dangers from low-temperature cooking
Using a vacuum sealer is not just more flavorful when you sous-vide. It also helps to keep your food safe from harmful bacteria. Sous-vide cooking is done in at a low temperature, in a moist environment, for a long time, which can be the ideal breeding ground for harmful bacteria and food-borne illness. Practicing good food hygiene and using a vacuum sealer help to reduce some of the risks of this kind of cooking environment.
Always seal your bags thoroughly, cook your food to the recommended temperature, and eat foods promptly. If you aren't vacuum sealing your food before cooking it sous-vide style, then it should be eaten quickly and not stored.
Sous-vide cooking was developed specifically for use with vacuum sealed food, and it remains the best way to take advantage of this exceptional cooking method. While it is not strictly necessary to own a vacuum sealer for cooking many foods in a sous-vide style, vacuum sealing does make it easier, safer, and more reliable to have excellent meals every time when immersion cooking.
Today, vacuum sealers are so available and so affordable for the home chef, there is really no reason not to invest in one of these machines. In addition to opening up the whole range of sous-vide foods, a vacuum sealer has a variety of other uses in the kitchen and the home, and you are sure to discover innumerable ways to use one.