Couple years ago when the FDA hammer was beginning to fall I bought craploads of Hangsen tobacco concentrates and RTS TA for the fear of them disappearing into the sunset. I proceeded to take all out of the 50ml original bottles and put into glass and cut the TA into smaller portions. They have been in the freezer for a couple years now and have pulled a few out in that time and they are just fine. I don't know about freezing other flavor concentrates but the tobacco ones I froze didn't change from being frozen. My glycube of PG/VG sit in a cold room and I cut out a quart at a time when needed. My nic in 500ml bottles and 50ml shots that make 100mls of 48nic to use. My mixed juices just sit at my desk on a shelf and in a closet. I don't know anymore or forgot about commercial juices to how to handle them since I DIY my juices. Heat steeping IMO just accelerates the degrading process with any juice.