Thats why I stressed getting the name brand freezer bags.

I like the retort bag idea-not a clue where to find them, and they are likely far too expensive to be practical. I havent had any issues with the quality bags at all. One thing I recommend is using some sort of cozy-I have a GSI cookset, and the pot comes is a rubberized fabric bag-I use that as a cozy. Worst case, if the bag leaked, it would leak into the rubberized bag-and I would still be fine. I am sure an insulated mug would work too, if it were large enoough.