the oak by its self will only flavor--needs more ,, o2, evaporating, and just time are some of the others.
barrels do this because they are porous and exchange o2. and some evaporates (angels share)also acids tannins etc. work with the alcohol.
but this takes time.to an extent the longer the better,some of this can be "hurried" up like bubbling o2 threw it.
Iv tryed some and they helped but found for the most part not worth the effort when you can just put it in a barrel and forget it for some time.
unless doing "in the white" then then air/o2 helps.
