Ok gotta chime in here. I think I vaccumm seal EVERYTHING. I put up a lot of food and have used both the re-hydration method that you have asked about and used it as a boiling bag and have never had a failure. I say this having never done it when this was the only thing to eat for 10 miles.

I am a little anal about my food storage though, I double seal top and bottom. The only thing I would warn about is reusing the bag. They loose something and I have had very poor luck the second time useing them. With that said, enjoy...