ANY slime or film on the bag will case a "loose" seal over time it will VERY slowly leaks out i made a jig up from duct work reducers that the bags fir over the reduced part about 4 inches just drop the fish in zoom complete clean seal.
I have 2 of them 2 different sizes on screwed on to a 1 x2 and then attach it to side of table big end up slide bag under small end drop fish in
Wet seals don't matter on chamber vac machines like they do on Foodsavers.. But if you are having that issue with a chamber machine on your seals then try turning the heat/seal time up a bit on your machine. Chamber machines are meant to be used on all kinds of wet foods. I use mine for soups, marinades, stews, sauces etc all the time and never worry about moisture on the seal area. A Foodsaver machine though, yup lot's of issues with that kind of thing.
View attachment 47321 Using a VP210 machine and half of my fish/bags turn out perfect the other half I find these little air bubbles after freezing. When I vacuum seal the fish, it looks perfect until I freeze.
Does anyone know what I am doing wrong?
If the fish is frozen solid when vac packing the bag can actually kind of stick/freeze to the fish in spots and leave little gaps (air pockets) around those areas.
To see if that's what the issue is simply quickly wet the piece a little bit that you are putting in the bag and see if it does the same thing. If not then you've found the issue. If it still does it with wet pieces you may have another issue with the timer setting on your vacmaster.. Make sure you have your timer setting set so that the needle drops below the green area completely. I go to the beginning of the "M" past the bottom of the green area to ensure full air removal.
Also make sure your oil is not under filled or overfilled. Both situations mess up the vacuum. I keep my oil half way on the bubble like the book says to do.
Edit: Sorry just re read your post and you say "after freezing" I was thinking frozen before vac packing.. If you look at that bag in your hand in the picture it looks like there is a little crease in the bag where it sealed. In that case any little crease in the bag will allow air to get in. Wet seal usually doesn't matter at all cause if the seal bar gets hot enough it cancels out any moisture where it is sealing but if there is a crease then yup for sure it will let air in there. You can avoid creases by leaving yourself extra room at the top of the bag where it is gonna seal then make sure the bag is put nice and flat and up and over the seal bar. If the bag is too full and the seal area of the bag gets scrunched up there when sealing then it will seal in little creases.
One other thing to consider too is your vacuum time can be different for different size pieces of food you are doing. The vacuum time is displacing air... you many not be getting 100% of the air displaced on some pieces so adjust your vac time more so it is removing all the air.