I'd think it dependent on how quickly you go
through it. I keep my nic base, PG/VG, flavors etc. in the basement with the wine. Nice and cool down there. If the liquid gets too cold (i.e. in the fridge), its constituents may tend to separate a bit. This could range from a slight cloudiness to precipitate such as maltose or sucralose crystals. It most likely won't make a difference when using it; just make sure to shake it up when you do. I mix 15 ml at a time and go through it in less than a week; this I keep wherever (as long as it's not too far from me). I'd say you should take the time to find a nice cozy spot for your
juice if its going to be sitting around for more than a week.