Maximum alcohol achieved by distillation is a little over 95%, which is indeed what some Everclear is sold at. A lot of places require Everclear to contain no more than 75% or so alcohol.
My guess is that smoother tasting vodka actually contains more “impurities”, albeit of a controlled kind.
Fuel ethanol comes close to 100%, but at a very high engineering and energy cost. All of the “fusel oils” are returned to the fuel ethanol stream, as they make for acceptable fuel too.
1) One of the large producers for Safeway and Lucky stores simply add distilled water to that 95% alcohol to bring it down to 80 proof.
2) The owners of that company were my neighbors in San Jose, CA. One night we all got together with several vodka "experts" for a blind taste test. Can't remember all the brands we used against the Safeway, however there were at least 8 or 9. In every case they picked the $3.99 bottle as the winner. Don't know exactly why but my thoughts were that the Safeway brand had not been flavored in any way.
An interesting side note: That same company opened a new distribution center in San Francisco and produced a new brand called Skyy Vodka. Exact same blend as the $3.99 stuff.
I enjoy Kamchatka as much as any of the high ends.
I’ve done a shot of pharmaceutical grade ethanol (99.5% de-ionized). It’s got more bite than 100 proof and is similar to Everclear.