For water bath cooking with sous vide, you cannot, obviously, just put your food straight into the water unprotected. It must be placed into the water via a water-tight container, and popular options include freezer bags, vacuum bags, and even glass canning jars to name a few.
While each one of these has merit for its own unique reasons, odds are good you'll see recipes that recommend using zipper freezer bags or vacuum bags most often.
But what is the difference between the two? We wanted to it down a bit more in this one, as once we switched to using vacuum bags we never looked back!