How are biodiesel and bioethanol made?

Bioethanolincluding bioethanol which is used in some countries as a fuel for cars and other vehicles, and bioethanol for domestic use in things such as biobased fireplaces, is a clear substance that is chemically the same as the ethanol that you probably know as the alcoholic component or alcoholic drinks. The term 'bioethanol' is used to describe ethanol produced by a specific process rather than the resulting chemical itself.

Bioethanol is made by using enzymes to break down biomass from a crop such as sugar cane, straw, certain grasses, wood chips or sawdust into sugars. The sugars are then fermented, after which a distillation process is used to collect the ethanol. The exact process differs depending on the type of crops used, but these are the essential stages in the production of bioethanol fuel.

Bioethanol is pure alcohol, and when it is sold for use in home fireplaces, it undergoes another process to ensure that no one tries to drink it, by turning it into what is called "denatured" alcohol. Alcohol of that purity is dangerous for human consumption, and in many countries illegal to sell as an ingredient, and so can only be sold in denatured form as fuel or in cleaning products.