Sous Vide (proncounced “soo vid”) is bascially about vacuum-sealing your meat (it doesn’t have to be a perfect vacuum), and heating it in a water bath sufficiently long for the meat to be heated to the perfect temperature all the way through. So what’s wrong with frying your steaks in the pan? Well, if your really good at it, you can produce greats steaks in the frying pan. However, the end result will always be a steak that’s more heavily fried on the outer parts than in the middle. There’s no way to avoid this when using a frying pan, because the heat is transferred from the pan to the middle through the outer parts of the steak. Thus, the outer parts will be overdone and less juicy than the perfect middle part. When using sous vide, the meat is vacuum-sealed in a plastic bag before going into the water bath, to avoid the meat getting into contact with the water directly. The water is then heated and precisely controlled to maintain a specific temperature (134 deg Fahrenheit or 57 deg Celcius for “medium-rare”), and the meat is left to cook for several hours (typically around two hours for sirloin, tenderloin). Because the water temperature never exceeds this temperature, no part of the steak is overdone. The result is perfectly cooked meat, with the precisely right pink color all the way through.