I don't know where these are shipping from/to, but you could throw a hand warmer in to the box to keep it warmer and carbonating while it's shipped. Some of them last 12 hours, and if the box is well insulated it could keep it warm for a while. As long as it doesn't get too hot - I have no idea how warm they get, but not hot enough to burn skin. It's probably not worth the risk unless you have a good idea of what will happen.