Some mixes are good right away, some must be steeped. Which is pretty much just giving them some time to get to know each other, and there are several different steeping methods. I haven't had to do that, so I can't help you there. BTW, the ratio of PG to VG will affect the flavor, it's PG that does the 'middle man' thing. More on the VG side does make the mix slightly (very slightly, IMO) sweeter.