In this application it does not matter what the sugar source was to make the ethanol. In liquor, the ethanol is usually 40-50%. The remaining is water and other miscellaneous substances that impart the flavor. Whiskey vs tequila. The non ethanol portion is the difference. In high quality vodka or grain alcohol it is distilled to 95%, diluted with pure water, then re-distilled. This "washes" out the flavor leaving only water. To make 100% ethanol you need to make an alternate azeotrope, I believe benzene would accomplish this, or treat it with a molecular sieve, a clay like substance that has a higher affinity for water than the ethanol.