I would wager that it is just an alcohol base or solution for the flavors in your liquid. Sometimes you can let them sit a couple of days, but don't be surprised if it takes 2-3 weeks for it to be best. EDIT*-I recommend getting a drip atomizer or two for this type of situation.
Liquids that don't use alcohol for a solution for flavorings won't necessarily taste better, but they will be sweeter EDIT*- if you let them sit for a period of time. I try to get smaller bottles in those flavors or go through them faster if I get a larger bottle.