Distillation - Ethanol from the fermented mixture is recovered by distillation process. The first distillation yields about 80% pure ethanol but by repeated distillation, ethanol concentration of 99.4% or more can be achieved. Final dessication can be achieved by chemical dessicants and by absorption.
In recent years, cellulose also seems to have become a distinct possibility as a renewable source of alcohol. Bagasses, sulphite waste, liquor of paper industry and agriculture biomass (hay) are the sources of cellulose.
The biomass is first pretreated through physical or chemical processes leading to reduction in size. This helps in hydrolysis of cellulose and hemicellulose by enzymatic or chemical treatment.