I mix a litre of base mix ( pg,vg,nic ) to my needs, which is 50/50 20mg, i leave that for a few days then use it as i need it, pour say, 50ml in a bottle then add say 5ml flavour, the base mix has already started to steep so you have a tiny head start, i then shake for a few mins, then lid off overnight, then another good shake, lid on and leave overnight, then lid off and shake as you please, i steep everything for at least 3 weeks, some as many as 7 weeks, it works for me, Stu