Posse member Mike Gagne uses sous vide to reheat a prime rib. (Photo ©Gary Jacobson/Texas BBQ Posse) Now it can be told. The Posse has gone all-in on sous vide. Well, not quite ALL. But we certainly have some strong sympathizers in our group. That became quite evident during a recent email discussion. It began on a lazy Friday afternoon and extended into the weekend. No better time to get philosophical about food. Sous vide, in short, is a method of cooking using sealed bags that are submerged in warm water. The technique was developed by a French chef…