What is PG?
PG is the conductor of the flavor orchestra. It carries the taste and provides the famous "throat hit" (that little scratchy feeling in the back of your throat). It's as thin as water and doesn't produce much vapor, but boy, does it wake up your taste buds.
Propylene Glycol is an organic compound used as an emulsifier in the food and cosmetic industries. Its low viscosity helps the cotton absorb the liquid. When heated, it vaporizes at a low temperature, preserving the molecular integrity of delicate flavorings.