Today I have been noticing that my favorite juice blend (18mg cool menthol + 2-3 drops 12mg Spearmint) which is normally very sweet and cool, tastes quite sour. I am using a Kanger EVOD. I have cleaned my tank and head, and this is the only juice I use in this one. does anyone know what could be causing this? 
Thanks
Liz
Thanks
Liz