Tee and Tatonka are spot on regarding the freezing. Beyond the liquid issue, if there are meats or preps you want to preserve the shape of (ex: meatballs, rolls, etc.) you may want to firm them up in the freezer as well prior to the sealing process. If you're trying to vacuum seal things like spices, where you worry about the intake of particulate matter, a very careful hand using the pulse function can accomplish the task.