does adding fat to the bag really help roasts come out more tender?

Hi @cathycatfish, that's a good question. While the fat adds flavor to the final dish, it's mainly through the sauce. It doesn't penetrate into the meat and studies have shown it doesn't affect the flavor of the meat itself. The moisture level and tenderness of the meat also aren't affected. <br /> <br />I know a few recipes in Beginning Sous Vide use the addition of fat to the dish, but lately I haven't been adding it to my dishes. If I want some more richness for leaner meats like the eye of round I'll add some extra fat to a sauce that I serve with the meat instead of into the bag itself. <br /> <br />I also agree with ElsieD, the eye of round makes great sandwiches and French Dips! <br /> <br />Hope that helps. Thanks and happy sous viding! <br /> <br />Jason Logsdon

I can't answer your fat question as I have never added fat, but i can tell you that I have cooked eye of round sous vide and it comes out incredibly tender. i cook it at 133 and it is perfect every time. Makes great sandwich meat. i know this doesn't answer your question but i thought you might be interested in the experience of one who has cooked eye of round this way. <br /> <br />Elsie