really the bottles I get from Unsmoke.us dont say anything but the nic level, flavor, ratio and born on date. But the bottles from cignot.com said to store the liquid in a "cool dark place or in the refrigerator for extended life". Its cool and dark in fridge so I have been keeping liquids in the fridge since I started vaping on 4/21. I know I had a bottle of RY4 go bad from being in the heat. Was in a hot mail truck for extra day instead of the normal day and half -2 days, but had a holiday and was in the hot truck a day longer only reason we could find it went bad all there other RY4 was good. The liquid was real nasty burnt tasting, and tried it in multiple attys. So I think I will keep the E-liquid in the fridge still but good info on not storing the attys in the fridge.