Steeping does not mellow out the flavors. Steeping would help bring the flavors out in a juice. For instance, when you buy juice from a store and say they mix it for you right then and there, you probably don't want to try it right away. So you would put it in a cool dark place for like a week or two so that the ingredients can mix and combine. Once you do this the flavor profile should become stronger and be a better vape. Now if you're buying from a high quality eliquid provider, since they make their juices in huge batches, chances are they've been sitting on a shelf or in a warehouse steeping before being mailed to you and therefore would be vapeable right out of the bottle.
