Without the angles share this fungus would not coat barrel houses. Wooden barrels allow some evaporation through the barrel, this is the angels share and those fums feed the angels share fungus/whiskey fungus. Spirits not aged in wood barrels are free from this.

From my understanding almost all spirits are watered down, things like Everclear being the exception. The modern still (which is quite old) produces alcohol over 90%, older less efficient stills use just as much fuel but have a higher methanol content which is not good for drinking and why they have fallen out of favor for distilling alcohol for drinking, still common for things like distilling essential oils.