A) keeps moisture from getting sucked up into the machine
B) provides a little extra layer of protection against freezer burn, should the seal fail for some reason

You can do this with anything that isn’t too soupy, but larger cuts of meat seem to work best for me.

When doing that partial freezing, be sure to set a timer to remind yourself to go back and seal it up. An hour usually is plenty for anything other than large items (like a brisket point or flat). Larger stuff might need an extra half-hour or so.

Here is another hack I used to use a lot when I had a food saver.
I make a lot of soups, stews and chowders, but was always discouraged from making large batches because I could not get them sealed in my food saver correctly to be saved for a later meal.
Try this:

This simple cup worked wonders for me.
Just make your soup, put out a few of these extremely cheap cups. Fill them 3/4 full (this is about the perfect serving size). Get them into the freezer. Once hard (not necessarily a complete block of ice), take a pair of scissors and cut down the sides top to bottom in three places. Then just peel off the cup and throw it away. You can now vacuum seal the ice block without any issues at all. Label them and enjoy at a future date. So go ahead and make those big batches of soup. Now you can seal them up with no mess and no hassle.

Freezing the food really does address one of the main disadvantage of non-chamber style sealers.

This simple cup worked wonders for me.
Just make your soup, put out a few of these extremely cheap cups. Fill them 3/4 full (this is about the perfect serving size). Get them into the freezer. Once hard (not necessarily a complete block of ice), take a pair of scissors and cut down the sides top to bottom in three places. Then just peel off the cup and throw it away. You can now vacuum seal the ice block without any issues at all. Label them and enjoy at a future date. So go ahead and make those big batches of soup. Now you can seal them up with no mess and no hassle.