Okay, now I have a starter and need a jar. Do I need something special. Certainly can do better than the expensive one from KA. My big question is does it have to have air flowing or does it need a tight seal? Can I use a mason jar with the metallic lid? Can I use a quart canister that has a rubber seal and a small metal clamp? Maybe it is not that important, but I want to do this right. Thanks for your help.