Ethanol (Tax-Paid) Purchasing 190- and 200-proof ethanol has never been easy, until now! Because these ethanols are federally regulated, a TTB permit is required to purchase 190- and 200-proof ethanol. Sigma-Aldrich takes the hassle out of this process for you. No TTB paperwork is needed, nor any records for you to keep. Sigma-Aldrich immediately pays the federal excise tax (200-proof pure alcohol=$27.00/gallon).