depends on the quality of the vacuum sealer and the product inside.
Because it does. It shouldn’t in theory, but in practice it does. I stopped worrying about it and just toss a piece of broken pizza stone on top, which allows plenty of circulation. I am working on designing a better system with parts from The Container Store but I have been too busy recently to actually get it done. I have to wait until my friend with all the fancy tools gets back from vacation. Large plastic box with cover cut to fit the large Anova, some sort of seal around the Anova to avoid evaporation, a plastic rack inside like a letter sorter or dish drainer to hold multiple bags, plus a plastic arm or grid over the rack to hold the bags in place.