Freezer bags are to freezers as zip files are to computers . . . they’re space savers!
First, I use this method—Paper Clamps in the Kitchen—to get some home made chicken stock in a plastic freezer bag.
Next, I zip the bag almost all the way shut leaving just enough space for air to escape. Then I squish out as much air as possible before completely sealing the bag.
Once frozen, the bags fit in the freezer a lot better.
And that is how to freeze flat!