I'm looking to get into sous vide cooking and have some questions to start, hoping to get some help here... 1. Does everything cooked sous-vide have to be vacuum sealed? Is it okay to just put the food in a zip-lock bag? 2. Is the vacuum sealing for sous-vide the same as for freezing? i.e. can I do it with one machine? 3. Is a sous vide container necessary? What's the advantage of using that versus a big pasta pot? 4. For food frozen in a vacuum sealed bag - should it be thawed, and resealed in a separate bag before cooking sous-vide? Thanks! Excited for this, also any recipes/videos on sous vide stuff welcome too!