I tried some backo the day I got it, no good. Let it steep for a week and a half and just took a chance today and filled up a brand new carto. It seems better (although I think I am just getting accustomed to how ejuices taste now) but now has a lemony-vomit taste to it (tastes fruity/lemony on inhale/in-mouth, and slightly vomit-like on exhale). So perhaps 4 weeks is best for a BWB tobacco flavor.