of food—or liquid—at a stable temperature: the beer cooler Here’s how it works: A beer cooler can keep things cool because it is a two-walled plastic chamber with air space between the walls The air space acts as an insulator, preventing thermal energy from the outside from reaching the cold food on the inside Of course, insulators work both ways—the cooler is just as good at keeping thermal energy on the inside from escaping to the outside Once you realize that a beer cooler is just as good at keeping hot things hot as it is at keeping cold things cold, the rest is easy: Fill your cooler with water just a couple degrees higher than the temperature you’d like to cook your food at (to account for temperature loss when you add the cold food), seal your food in a zipper-lock freezer bag, drop it in, and close your cooler Leave the food there until it is cooked It’s as simple as that But What About the Vacuum? Surely vacuum-sealing the food is an essential step in effective sous-vide cooking? As it turns out, not really The main reason to vacuum-seal food is that any air bubbles trapped inside the plastic bag can act as an insulator, preventing the food from cooking evenly As long as you can get all the bubbles out of your bag, there’s no reason it shouldn’t work just as well as a bag sealed with a vacuumsealer and there’s an easy way to do just that This technique was demonstrated for me by Dave Arnold, an instructor at the French Culinary Institute and contributor to the Cooking Issues blog (www.cookingissues.com): Place your food inside a zipper-lock freezer bag and seal it, leaving the last inch unsealed Holding on to the bag, slowly lower it into a large pot, cooler, or sinkful of water, using your hands to release ...But What About the Vacuum? Surely vacuum-sealing the food is an essential step in effective sous-vide cooking? As it turns out, not really The main reason to vacuum-seal food is that any air... air bubbles trapped inside the plastic bag can act as an insulator, preventing the food from cooking evenly As long as you can get all the bubbles out of your bag, there’s no reason it shouldn’t work just as well as a bag sealed with a vacuumsealer and there’s an easy way to do just that... shouldn’t work just as well as a bag sealed with a vacuumsealer and there’s an easy way to do just that This technique was demonstrated for me by Dave Arnold, an instructor at the French Culinary Institute and contributor to the Cooking Issues blog (www.cookingissues.com):