Originally Posted by JMediger
We keep emergency kits in our cars during the winter and I would prefer to bag water rather than buy 12 bottles that never get used. I know they will freeze so I'll have to play with how much air to leave in the bag.
Come from the opposite direction. Try putting water in a pint foodsaver bag (do not seal), lay it flat in a container and freeze. Then vacuum seal the ice block. Ice 'shrinks' when it thaws, so by freezing it first you should establish the maximum the water will freeze to frozen. Theoretically anyway. I've never tried refreezing the second time.
I did this originally attempting to create an emergency water pouch with no air in it, but I forgot that ice shrunk when thawed, so that idea was dumped.
Let us know how successful you are.