ETHANOL: Ethanol is made in two ways, one biological and one chemical. We will cover the biological only for now.
By fermentation – the biological way : Ethanol is made from glucose using yeast, in the absence of air

Yeast is a mass of living cells. The enzymes in it catalyse the reaction.
The process is called fermentation, and it is exothermic.
Ethanol can be made in this way from any substance that contains sugar, starch, or cellulose. (These break down to glucose.) For example it can be made from sugarcane, maize, potatoes, and wood.
The yeast stops working when the % of ethanol reaches a certain level, or if the mixture gets too warm.
Theethanol is separated from the final mixture by fractional distillation.