Select a target final temperature for the meat:
For beef strip or rib-eye steak — 144 degrees for medium, 133 degrees for medium-rare, 129 degrees for rare
Beef filet — 144 degrees for medium, 127 degrees for medium-rare, 122 for rare
Chicken breast — 140 degrees for medium, and hold at this temperature for at least 20 minutes to pasteurize
Salmon fillet — 113 degrees for rare, 126 degrees for firm
Once you select your target final temperature, add 15 degrees to that. This is the temperature to which you must heat your water. For example, to cook a beef strip steak medium rare (133 degrees), the water should be heated to 15 degrees above that, or 148 degrees. Heat 8 quarts of water per piece of meat to the temperature you calculated, dump it into the cooler and close the lid tightly.
Wash your hands well with soap. Place each steak, breast or fillet in an individual zip-close plastic bag. Add about 1 tablespoon of cooking oil to each bag.
It is important to remove as much air as possible from each bag so that it does not float and the water can transmit heat to every part of the food. Before sealing the bags, open the cooler. One at a time, hold each bag by its open end and slowly lower it into the water until the water level is just below the seal. The water will push the air out of the bag. Seal the bag tightly. The sealed bag should sink. Repeat with the remaining bags of food. Space the food in the bottom of the cooler so that water can circulate easily around each bag.
Close the cooler lid firmly, and cook until the meat warms to the target temperature. Expect inch-thick steaks to reach medium-rare in 50 to 60 minutes; salmon fillets of that thickness may take only 20 minutes. Chicken breast may reach 140 degrees in 30 to 40 minutes, but must be held at that temperature or higher for at least 20 minutes more in order to pasteurize them.
Remove the meat from the bags and place it on a rack or baking sheet. If you want to sear the surface of the meat, sweep the flame of a blowtorch over each side in a series of quick, even passes, or place it on a very hot grill until browned.
Season generously with salt, and serve immediately.