Vape Juice Turning Liquid. Last time it turned completely yellow. The most common culprit in vape allergic reactions is propylene glycol (pg), a commonly used base in vape juice.
Make sure that the tank. This caramelization causes the sugars to break down or separate, which results in the vape juice turning brown. Pg can cause allergic symptoms ranging from a scratchy throat to sinus problems, headaches, and even feelings of nausea.