Nearly every recipe for making vanilla extract suggests the use of Vodka, or an alternative alcoholic beverage with a high alcohol content (typically 35%+), such as Rum or Bourbon. However, the various recipes typically default to Vodka for its more neutral taste. Essentially, the recipes simply instruct to leave opened vanilla pods in the alcoholic beverage for at least several months. The high alcohol percentage is required for the vanilla flavour to diffuse over time.
This made me wonder why I cannot find a single recipe that simply recommends the use of pure food grade ethanol, like that used to make Limoncello or other fruit- or herb-based liquors. It is typically cheaper, does not add additional flavour, and its high alcohol percentage (typically 95%+) (Rectified spirit) should suggest a better diffusion of flavours, or not? What am I missing?