vg

[Time]

Can't get condensation inside the bottles unless there is already water inside. They won't freeze because they are pg based but some like TFA bavarian cream will separate when cold. When it warms up, it mixes back together with shaking. I quit putting them in the freezer because it was a pain in the ass to get them all back out and warm them up every time I mix. The freezer didn't hurt any of them.

 

[HeadInClouds]

I would not freeze the flavor concentrates, no. Some of them might actually freeze, I'm not sure, but when flavoring goes from very cold to room temperature, there's condensation inside the bottle. That can invite bacteria.

They're unlikely to freeze, because most are based on VG, PG, alcohol, or some combination. In those that separate into layers, some layer might freeze.

I would disagree that condensation "invites" bacteria. Bacteria cannot spontaneously generate if it wasn't present in the sealed bottle to begin with. And if there IS bacteria already there, keeping it as cold as possible would actually slow the growth.

 

[Teresa P]

I just took it as fair advice when I was told, but I'm somewhat of a "germaphobe." I'm leery of anything airborne, just habit from dealing with a severely asthmatic husband who catches everything....not Howard Hughes bad, but bad enough.