I mix it for the wife & use about 5% concentrate. I just try a couple of puffs & if it tastes ok then I feed it to her. I have found that some concentrates can be stronger than others so the amount you add can vary. Best to add small amounts & try it rather than add too much. Remember not to mix it into a large amount of your eliq until you are sure about how much to add of a particular concentrate. Menthol is strong so you tend to need less of it that some flavours. When my present batch runs out (I mix it aroung 1/2 a litre at a time 50% PG-50% VG as its cheap) I am going to get some menthol crystals from boots & dissolve them in PG liquid to make my own concentrate. At least that way it will be consistant, and cheap. So it will be 50% crystals to 50% PG, giving it an occasional stir. They wont disolve in VG liquid.
