In the past, I used nic from Nicotine River and was very happy with it. Now I'm using nic from Heartland Vapes. I keep an unopened bottle in the freezer, but I foolishly kept the working bottle in the fridge. It was fine when I got it but now has just a slight yellow color. What's left is now in the freezer. The problem is the last time I mixed up some unflavored "base", it tasted strong and bitter. I have recently learned it can separate while stored... I never shake it (even when using it) so wondering if it's actually OK and just separated. I'm OCD about shaking my mixed base and mt actual mixed juices... just forgot to shake the nic. Obviously, I will shake it before using the next time. Should I shake the bottles that are in the freezer (maybe once a week)... would that help? They are 50VG/50PG is that matters (I did prefer when my nic was just PG... easier to pour into a funnel)