Four hours is just the minimum. Sometimes my internal watch is a bit slow when beer is involved. The best part is the longer you cook that sucker the better. It is not a time sensitive operation as long as it is enough time. If there was any prions present I am sure they swirl down the hole with the rest when I trigger the lever. You have a better chance of getting hit in the head by a meteorite than getting CWD. In the history of mankind only one of the two things has actually happened.